Extended release amphetamine compositions

ABSTRACT

An oral amphetamine extended release liquid suspension is described. The compositions contain a combination of an uncoated amphetamine-cation exchange resin complex, a barrier coated amphetamine-cation exchange resin complex-matrix, and an uncomplexed amphetamine, wherein one or more of these components contains blends of different forms of amphetamines. Either the modified release coated and/or the uncoated amphetamine-cation exchange resin complex may have two forms of amphetamine in a complex with a single cation exchange resin. Following administration of a single dose of the composition, a therapeutically effective amount of amphetamine is reached by about one hour and the composition provides at least a thirteen hour effect post-dose.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 15/258,695, filed Sep. 7, 2016, which claims the benefit of priority under 35 USC 119(e) of U.S. Provisional Patent Application No. 62/215,301, and U.S. Provisional Patent Application No. 62/215,304, each filed Sep. 8, 2015. These applications are incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

Amphetamine (contracted from alpha-methylphenethylamine) exists as two stereoisomers (enantiomers): levoamphetamine and dextroamphetamine. Amphetamine refers to the racemic free base, which are equal parts of the two enantiomers in their pure amine forms. Amphetamine is a potent central nervous system (CNS) stimulant of the phenylethylamine class that is used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy [see. e.g., Adderall® IR Prescribing Information”. United States Food and Drug Administration. Barr Laboratories, Inc. March 2007. pp. 4-5. Retrieved 2 Nov. 2013], was at one time used as an appetite suppressant, and has been reported to sometimes be prescribed off-label for its past medical indications, such as depression, obesity, and nasal congestion [Heal D J, et al (June 2013). “Amphetamine, past and present—a pharmacological and clinical perspective”. J. Psychopharmacol. 27 (6): 479-496; S. Berman et al, Mol Psychiatry, February 2009; 14(2): 123-142]].

Pharmaceutical drugs classed as amphetamines include formulations containing salts of d-amphetamine (DextroStat®, Dexedrine®), mixed d- and l-amphetamine (Adderall®), d-methamphetamine (Desoxyn®), and a d-amphetamine pro-drug compound, lisdexamfetamine dimesylate (Vyvanse®). Reports of abuse of amphetamines date back to shortly following introduction of injectable forms of amphetamine. See, Berman et al, cited above. Because of its abuse potential, amphetamine and its salts, optical isomers, and salts of its optical isomer, are Schedule II substances controlled by the US Food and Drug Administration. 21 CFR. Sec. 1308.12 Schedule II. Amphetamine abuse has been reported to lead to tolerance and physical and psychological dependence, and is characterized by consuming increasingly higher dosages, and by the “binge and crash” cycle, when users attempt to maintain their high by overindulging on these drugs. Berman et al, cited above.

Both Adderall® (immediate-release) tablets and Adderall® XR capsules contain d-amphetamine and l-amphetamine salts in the ratio of 3:1. Following administration of Adderall® (immediate-release), the peak plasma concentrations occurs in about 3 hours for both d-amphetamine and l-amphetamine. The time to reach maximum plasma concentration (T_(max)) for Adderall® XR is about 7 hours, which is about 4 hours longer compared to Adderall® (immediate-release) [http://www3.us.elsevierhealth.com/-DrugConsult/Top_200/Drugs/e3289.html]. There have been reports of rebound effects with long-acting amphetamine products such as Adderall® XR [D J Cox, et al, Journal of Child and Adolescent Psychopharmacology. February 2008, Vol. 18, No. 1: 1-10]. Symptoms include irritability, excessive talking, hyperactivity and insomnia. See, also, S. M. Berman et al, Mol Psychiatry. 2009 February; 14(2): 123-142, which reports on the history of the medical use of amphetamines since the early twentieth century.

US 2003/0099711 describes compositions comprising drugs bound to ion exchange resin particles and coated with a water-permeable, film-forming polymer. Among the several dozen drugs listed are amphetamine and dextroamphetamine. U.S. Pat. No. 4,996,047 also describes dozens of drugs, including amphetamine and dextroamphetamine, which may be selected to be bound to a ion exchange resin and coated with a water-permeable diffusion barrier coating. See, also, U.S. Pat. No. 2,990,332 (ionic exchange resin complexes with amphetamine).

US Reissue Patents 41,148 and RE 42,096 describe oral pulsed dose amphetamine delivery systems having an immediate release amphetamine and a delayed enteric release amphetamine component with mixed amphetamine salts. Among the specific amphetamine salts described are dextroamphetamine sulfate, dextroamphetamine saccharate, amphetamine aspartate monohydrate, and amphetamine sulfate, which are present in Shire's Adderall® product [see, Adderall® product literature]. It has been reported that the four salts are metabolized at different rates and have different half-lives, resulting in a less dramatic onset and termination of therapeutic action as compared to a single salt amphetamine preparation. S M Berman et al, Mol Psychiatry, February 2009: 14(2):124-142.

U.S. Pat. No. 7,776,917 refers to a conjugate comprising amphetamine and homoarginine, a salt of the conjugate, or a combination thereof.

U.S. Pat. No. 8,343,546 describes the treatment of an ion exchange resin with one or more sugar alcohols in order to prevent swelling. Amphetamine is identified amongst the many drugs which may be bound to the ion exchange resin.

U.S. Pat. No. 8,597,684 describes a composition containing a mixture of a pH-independent, modified release barrier coated amphetamine-ion exchange resin complex, an uncoated amphetamine-ion exchange resin complex, and an optional uncomplexed amphetamine or salt thereof. See, also, e.g., U.S. Pat. No. 8,883,217, which was also published as US 2014/0127306 and related U.S. Pat. No. 8,062,667. A subsequently published document, US 2013/0243869, refers to a pharmaceutical composition in which an ADHD-effective agent is complexed with ion exchange resin particles to form drug-resin particles, wherein said ADHD effective agent is a mixture of dextro- and levo-amphetamines. The composition may contain a mixture of uncoated drug-resin particles and a delayed-release coated drug-ion exchange resin complex. US 2014/0050796 describe mixtures of dextro- and levo-amphetamine complexed with ion exchange resin particles which comprise 20 to 50% uncoated drug-resin particles and 50 to 80% drug-resin particles coated with a delayed release coating.

US 2014/0050796 reports that its compositions offer advantages over Adderall® XR by minimizing the amount of sulfates used. This document reports that such sulfate compounds could form alkyl sulfonates and that the FDA recommends limiting or excluding alkyl sulfonates from drug formulations. This document also reports that the presence of ethanol causes dose dumping in Adderall® XR, which dose dumping the authors claim is minimized in their composition. In one embodiment [Paragraph 0019], the compositions of the '796 application are substantially free of dextroamphetamine saccharate and/or amphetamine aspartate.

US 2004/0220277 and WO 2004/071501 describe amphetamine compositions in which the molar ratio of l-amphetamine to d-amphetamine released therefrom in a time period later in the day is higher than the ratio released in a time period earlier in the day. These applications permit delivery of l-amphetamine and/or d-amphetamine as separate enantiomers, optionally delivered in combination with the racemic dl-amphetamine.

US 2013/0079415 describes drugs comprising an amphetamine or a salt thereof and an amphetamine pro-drug lisdexamphetamine.

There remains a need for a quick-acting, stable, extended release amphetamine product which can be conveniently delivered in a form suitable for patients who have difficulty swallowing whole tablets and capsules.

SUMMARY OF THE INVENTION

Amphetamine extended release compositions are described which provides in a single composition an immediate release of amphetamine with a fast onset of therapeutic effect and a therapeutic effect through an extended release. Liquid suspension are provided. Also provided are tablets which are both chewable and orally disintegrating. These compositions provide easy administration for patients who have difficulty swallowing pills, especially for the pediatric and geriatric patients. Further because chewing does not alter the extended release properties of the product, patients have option to swallow, dissolve in the mouth (buccal cavity) or to chew a solid unit dose tablet without affecting the release property of the product. Additionally the compositions can be dose titrated without altering the release profile of the composition, i.e., by administering different volume of the liquid suspension or splitting the tablet. Methods of treating patients in need thereof with these amphetamine (AMP) extended release compositions are further provided.

In one aspect, an orally administrable extended release amphetamine composition comprising: (A) a modified release amphetamine component which comprises at least one modified release barrier coated amphetamine-cation exchange resin complex-optional matrix which comprises (i) two or more amphetamines both bound to the same cation exchange resin or each bound to a different cation exchange resins, wherein when the optional matrix is present, the amphetamine-cation exchange resin complex-matrix further comprises a hydrophilic polymer or copolymer or a hydrophobic polymer and (ii) a water-insoluble, water-permeable, non-ionic modified release barrier coating which provides a modified release to the two or more amphetamines, wherein the two or more amphetamines at least a d-amphetamine and an l-amphetamine, wherein the d-amphetamine and the l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine and l-amphetamine; (B) a first immediate release amphetamine component which comprises d-amphetamine or a pharmaceutically acceptable salt thereof, and l-amphetamine or a pharmaceutically acceptable salt thereof, or mixtures thereof, wherein the d- and l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine and l-amphetamine; (C) a second immediate release amphetamine component which comprises an amphetamine-cation exchange resin complex in an optional matrix, wherein the amphetamine-cation exchange resin complex-optional matrix comprises at least a d-amphetamine and an l-amphetamine both bound to the same cation exchange resin or each bound to different cation exchange resins, wherein the d-amphetamine and the l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine or l-amphetamine; wherein the composition provides at least one immediate release profile for d-amphetamine and for l-amphetamine and an extended therapeutically effective release profile of at least 13 hours for d-amphetamine and for l-amphetamine; wherein the composition comprises a ratio of about 3 parts by weight d-amphetamine to about 1 part by weight l-amphetamine; wherein, following a single dose of the composition in pediatric patients aged 6 to 12 years, geometric mean plasma AUC_(0-∞) of about 910 h*ng/mL to about 1115 h*ng/mL for d-amphetamine and about 245 h*ng/mL to about 400 h*ng/mL for l-amphetamine and a geometric mean plasma C_(max) of about 45 ng/mL to about 60 ng/mL for d-amphetamine and about 14 ng/mL to about 18 ng/mL for l-amphetamine.

In another embodiment, the composition of the invention contains only two counterions to the amphetamines.

In one aspect, the immediate release, modified release, titratable amphetamine composition is an orally administrable liquid suspension product. In one embodiment, the total amphetamines in the suspension are provided by a modified release component in an amount of about 45% to about 75% of the amphetamine, at least about 5% to about 25% of the amphetamine is provided by immediate release component (B), and at least about 5% to about 35% of the amphetamine is provided by immediate release component (C).

In another aspect, the immediate release, modified release, titratable amphetamine composition is a chewable tablet, which is optionally scored for accurate, easy division or splitting. In such an embodiment, the modified release component (A) may comprise about 70% of the total amphetamines in the tablet, based on the weight of the free base of the amphetamines, and further wherein the immediate release component (C) comprising the amphetamine-cation exchange resin complex provides about 10% of the total amphetamines in the tablet, wherein the weight is measured on the basis of free base of the amphetamines

In one embodiment, a chewable tablet as provided herein is further characterized by also being an orally disintegrating tablet. In a further embodiment, the invention provides a method of treating patients with a disorder for which amphetamines are regulatory approved by administering an amphetamine extended release composition as described herein.

Still other aspects and advantages of the invention will be apparent from the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a graph of SKAMP results in pediatric patients aged 6 to 12 diagnosed with attention deficit hyperactivity disorder (ADHD), following administration of the patient appropriate doses in the range of 2.5 mg/mL to 20 mg/8 mL of the oral suspension product of Example 1 described herein containing 20 mg/8 mL suspension. The results show therapeutic effect throughout the range of times tested, from one hour to 13 hours post-dosing.

FIG. 2 is a graph showing the plasma concentration profile for d-amphetamine following a single dose of the suspension of Example 1 to pediatric subjects ages 6-12 under fasting conditions, at a dose equivalent to 10 mg amphetamine base.

FIG. 3 is a graph showing the plasma concentration profile for l-amphetamine following a single dose of the suspension of Example 1 to pediatric subjects ages 6-12 under fasting conditions, at a dose equivalent to 10 mg amphetamine base.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides amphetamine extended release compositions in which at least two different forms of amphetamine are provided in different release profiles, i.e., a modified release amphetamine component and an immediate release amphetamine component. In one embodiment, there is more than one immediate release component, one of which has a faster onset, e.g., up to about 100% of this faster onset is released within about 10 to about 20 minutes, and a second immediate release component, e.g., up to about 100% is released within about 1 hour. In one embodiment, at least two different amphetamine compounds (e.g., racemic amphetamine and d-amphetamine or salts thereof) are present in each of the modified release and immediate release profiles.

As used herein, the term “amphetamine”, abbreviated herein “AMP” is used to refer to generally to amphetamine compounds, encompassing racemic amphetamine and the separate enantiomers thereof: dextro- or dex-(d)-amphetamine, and/or levo (l)-amphetamine. Racemic amphetamine is also termed herein (d,l)-amphetamine and is generally understood to contain a 1:1 ratio of d- to l-amphetamine. However, a racemate produced containing another ratios of these enantiomers may be used in the preparing the compositions described herein. Methods of preparing optically pure amphetamine enantiomers have been described. See, e.g., U.S. Pat. Nos. 3,028,430; 2,906,665A (l-amphetamine alginate); U.S. Pat. No. 6,399,828 (preparing amphetamines from phenylpropalamines); U.S. Pat. No. 8,487,134B2 (production acylated amphetamine, dexamphetamine and methamphetamines), the disclosures of which are incorporated by reference. Various amphetamine active pharmaceutical ingredients (API)-grade compounds can be purchased commercially (e.g., Gyma Laboratories of America, Cambrex, Johnson Matthey). Typically these compounds are purchased in the form of a pharmaceutically acceptable salt thereof, such as the mesylate, hydrochloride, saccharate, sulfate, aspartate salt, or a hydrate of such a salt. These or other pharmaceutically acceptable salts include e.g., non-toxic, inorganic and organic acid addition salts, are known in the art. Exemplary salts include, but are not limited to, 2-hydroxyethanesulfonate, 2-naphthalenesulfonate, 3-hydroxy-2-naphthoate, 3-phenylpropionate, acetate, adipate, alginate, amsonate, aspartate, benzenesulfonate, benzoate, besylate, bicarbonate, bisulfate, bitartrate, borate, butyrate, calcium edetate, camphorate, camphorsulfonate, camsylate, carbonate, citrate, clavulariate, cycloperitanepropionate, digluconate, dodecylsulfate, edetate, edisylate, estolate, esylate, ethanesulfonate, fumarate, gluceptate, glueoheptanoate, gluconate, glutamate, glycerophosphate, glycollylarsanilate, hemisulfate, heptanoate, hexafluorophosphate, hexanoate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroiodide, hydroxynaphthoate, iodide, isothionate, lactate, lactobionate, laurate, laurylsulphonate, malate, maleate, mandelate, mesylate, methanesulfonate, methylbromide, methylnitrate, methylsulfate, mucate, naphthylate, napsylate, nicotinate, nitrate. N-methylglucamine ammonium salt, oleate, oxalate, palmitate, pamoate, pantothenate, pectinate, persulfate, phosphate, phosphate/diphosphate, picrate, pivalate, polygalacturonate, propionate, p-toluenesulfonate, saccharate, salicylate, stearate, subacetate, succinate, sulfate, sulfosaliculate, suramate, tannate, tartrate, teoclate, thiocvanate, tosylate, triethiodide, undecanoate, and valerate salts, and the like. In one embodiment, in the compositions described herein, the saccharate salt form of the amphetamine is not selected for use in a composition where the counterion will be present in the composition.

As used herein, a “counterion” is the ion that accompanies an ionic species (e.g., an amphetamine base) in order to maintain electric neutrality. For example, when an amphetamine salt is dissolved, the “counterion” is the dissociated ionic species, e.g., from an amphetamine saccharate, the saccharate would be the counterion.

Although not encompassed with the term “amphetamine”, it will be understood that derivatives, prodrugs (e.g., esters), and/or preprodrugs of the racemic amphetamine, dex(d)-amphetamine, or l-amphetamine, may be selected for use in a composition described herein. One example of such a drug includes, e.g., lisdexamphetamine. Methods for producing such derivatives, prodrugs and preprodrugs have been described. See. e.g., U.S. Pat. No. 8,487,134 (production of acylated amphetamine, dexamphetamine and methamphetamines); US20120157706 (methods and compositions for preparing lisdexamfetamine and salts thereof), the disclosures of which are incorporated herein by reference.

In one embodiment, the compositions provided herein are described as containing a total ratio of d- to l-amphetamine of about 3 parts by weight d-amphetamine to about 1 part by weight l-amphetamine (e.g, 2.60 parts by weight to 3.40 parts by weight d-amphetamine, or 3 parts by weight to 3.4 parts by weight d-amphetamine, or about 3.2 parts by weight d-amphetamine) to about 1 part by weight l-amphetamine. Further, the modified release and/or one or both of the immediate release components may also contain a similar ratio. When making this calculation, the total d-amphetamine amount is used, regardless of whether contributed by the racemate or the dexamphetamine enantiomer. Unless otherwise specified, the racemate contains 50% d- and 50% l-amphetamine. Throughout this specification, when weight percentages and/or ratios are provided for amphetamines in each of the active components, the weight percentage or ratio is calculated based on the amount of amphetamine base in each component.

As used herein the term “uncomplexed” refers to an amphetamine, refers to the faster onset immediate release component, wherein a second immediate onset component is present, and specifically includes the corresponding amphetamine free base, as well as pharmacologically active and physiologically compatible salts form thereof, including acid addition salts, hydrates thereof, and hydrates (anhydrous, semihydrates, etc) of these salts; specifically excluded from the term “uncomplexed amphetamine” is an amphetamine which bound to or complexed with a cation exchange resin.

The immediate release amphetamine component also comprises an amphetamine-cation exchange resin complex, optionally in combination with a matrix forming polymer which is characterized herein as the “slower” onset immediate release component. This component may be referred to as “uncoated” in that it may contain no coating, or if any coating is present, the coating either does not function to modify the release characteristics of the drug (from immediate release to modified release). This slower onset immediate release component may contain a blend of two separate uncoated amphetamine-cation exchange resin complexes, each of which contains a single amphetamine component bound to a cation exchange resin (e.g., (d,l)-amphetamine-cation exchange resin complex and/or d-amphetamine-cation exchange resin complex). Alternatively, two different amphetamines may be bound to a single cation exchange resin complex (e.g., both (d,l)- and d-amphetamine-cation exchange resin complex). Methods for loading multiple drugs onto a single resin have been described. See. e.g., U.S. Pat. Nos. 8,062,667, 8,329,224 B2 and Published Patent Application No. 2007-0148239, which describes multiple loadings onto an ion exchange resin; and WO 2007/001300, which generally describes drug loading and conjugating more than one active drug with a single resin particle, the disclosures of which are incorporated by reference herein. In still another embodiment, compositions may be produced in which amphetamine-cation exchange resin complexes containing multiple amphetamines (e.g., dl-,d-amphetamine-cation exchange resin complex) and containing a single amphetamine (d-amphetamine-cation exchange resin complex) are combined. The immediate release component contains a plurality of particulate, amphetamine-cation exchange resin complexes.

As used herein, the term “modified release” refers to components in which the release of at least one of the active components (i.e., (d,l)-amphetamine, d-amphetamine or l-amphetamine) is longer than its immediate release form. “Modified release” may encompass sustained release, extended release, or delayed release. For convenience, “modified release” is used to refer to the amphetamine component of the composition, whereas “extended release” is used to refer to the present composition which provides both immediate release and modified release components. In one embodiment, the modified release profile extends to at least 8 hours. More desirably, the composition provides a therapeutic effect through at least about 12 hours to about 18 hours, about 13 hours to about 16 hours, or about 13 hours. The release profile may be assessed via in vitro dissolution using techniques known to those of skill in the art [e.g., USP basket method, paddle method, channel flow method, or other methods known in the literature]. The release profile can be assessed in vivo (e.g., for bioavailability determinations), using plasma concentrations to assess maximum plasma concentration (C_(max)) and area under the curve (AUC).

A therapeutic result for amphetamine is not solely related to plasma levels of the drug. Thus, “a therapeutically effective amount” of amphetamine includes the minimum amount of the drug required to provide a clinically observable psychological and/or behavioral response. Unless otherwise specified, this is determined following a single or “initial” administration of an extended release amphetamine composition as described herein. A therapeutically effective amount of amphetamine can alternatively be defined as being at least the minimum amount of amphetamine which reduces or eliminates the symptoms associated with a condition for which amphetamine has been approved for use. Appropriate doses are discussed in more detail later in this specification. Therapeutic effect may be assessed, e.g., by the Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) deportment scale throughout the day [Wigal S B, et al, Psychopharmacol Bull, 1988: 34(1): 47-53]. Other suitable assays and methods may be selected by one of skill in the art.

The term “initial administration” is defined for purposes of the present invention as the first single dose of an extended release amphetamine composition administered to a patient or subject or the first dose administered to a patient or subject after a suitable washout period. As used herein, the term “patient” and “subject” are used interchangeably to refer to humans who are being dosed with an extended release amphetamine composition as provided herein.

The modified release component has a coating which provides a modified release profile to the amphetamine(s). The coating is over the amphetamine-cation exchange resin complex, which is optionally in a matrix. As described in more detail below, the modified release component may contain a blend of two different modified release, pH-independent, barrier coated-amphetamine-cation exchange resin complexes, each of which contains a single amphetamine component bound to a cation exchange resin. Alternatively, at least two different amphetamines may be bound to a single cation exchange resin complex (e.g., (d,l)-amphetamine, d-amphetamine, and/or l-amphetamine), using methods such as are described herein. In still another embodiment, compositions may be produced in which two or more different amphetamines on the same cation exchange resin is combined with a single amphetamine bound to a separate cation exchange. The resulting modified release component contains a plurality of particulate, barrier coated amphetamine-cation exchange resin complexes, which are separately coated with a pH-independent release, high tensile strength, water insoluble, water-permeable modified release barrier coating prior to be admixed with the immediate release components. In the compositions described herein, typically, the excipients are selected such that they do not contribute at all, or to any measurable amount, to the modified release properties of the composition.

Whether selected from the racemate (d,l), or the separate enantiomers: d-amphetamine or l-amphetamine, the active drug may be present in the form of a salt, hydrate, or hydrate of a salt. One suitable salt is the saccharate, succinate, hydrochloride, aspartate or sulfate salt form. However, other pharmaceutically acceptable salts may be selected.

As used herein, the term “free amphetamine” refers to the weight of the amphetamine base, i.e., exclusive of any salt, hydrate, polistirex or complex form.

In one embodiment, an amphetamine extended release chewable tablet of the invention contains amphetamines in different forms, (a) a modified release barrier coated amphetamine-cation exchange resin complex, optionally in a matrix, (b) a slower onset immediate release uncoated amphetamine-cation exchange resin complex, optionally in a matrix, and (c) a faster onset immediate release uncomplexed amphetamine. The modified release, barrier coated amphetamine-cation exchange resin complex, optionally in a matrix, may contain a mixture of one or more of (d,l)-amphetamine, d-amphetamine and/or l-amphetamine complexed on separate ion exchange resins, or a mixture of d-amphetamine and l-amphetamine complexed onto the same cation exchange resin complex.

The compositions provided herein are characterized by providing both immediate release amphetamine and modified release amphetamine. The term “immediate release” (“IR”) refers to the release of an active ingredient (e.g., an amphetamine) from a pharmaceutical formulation where the rate of release of the active pharmaceutical ingredient from the pharmaceutical formulation is not substantially retarded by means of a controlled release matrix or other such means and where the components of the pharmaceutical formulation are designed such that, upon ingestion, maximum exposure of said active pharmaceutical ingredient to body tissues occurs in the minimum period of time. As described herein, an “immediate release” amphetamine component releases about 100% in less than 1 hour. The present invention provides for an extended release composition having two different immediate release amphetamine components, each of which provides a different release profile.

In one embodiment, at least one of the immediate release components provide a faster onset, i.e., release of about 100% in less than 30 minutes, with at least 50% release in less than 20 minutes and, preferably in as few as ten minutes, or sooner. In some embodiments, 80 to 100% is released within about 10 to 20 minutes, or about 10 minutes. This immediate release component is an uncomplexed amphetamine. A second, different, immediate release component provides a different immediate release pharmacokinetic profile, which releases in less than about an hour, as soon as about 30 minutes, or as soon as about 20 minutes, with at least some measurable release as early as about 10 to 15 minutes. Typically, this immediate release component does not release as quickly as the faster onset immediate release component. Suitably this slower onset immediate release component is an uncoated amphetamine-cation exchange resin complex, which is optionally in a matrix with a matrix forming polymer. When present in the immediate release component, the matrix forming polymer is selected so that the resulting uncoated amphetamine-cation exchange resin complex (optionally in a matrix) retains an immediate release profile. For convenience, the optional matrix is not referenced in every phrase where the uncoated complex is discussed. However, it will be understood that this uncoated complex may contain such a component. The release profiles of the two different immediate release components may overlap, e.g., the slower onset immediate release component may begin releasing before 100% of the faster onset immediate release component is completely released.

In one example, the modified release barrier coated amphetamine-cation exchange resin complex, optionally in a matrix provides an amount of about 45% w/w to about 90% w/w, about 50% w/w to about 80% w/w, or about 60% w/w to about 75% w/w of the total amphetamine components in the composition (based on the free amphetamine base(s)). The two immediate release components combine to provide about 10% w/w to about 55% w/w, about 20% w/w to about 40% w/w, or about 25% w/w to about 35% w/w of the total amphetamine components in the composition. The uncoated amphetamine-cation exchange resin complex component is designed to be immediate release as defined herein, and as such, does not contain a coating which functions to delay release (e.g., no functional amount of an extended release barrier coating or enteric coat). Suitably, immediate release amphetamine-cation exchange resin complex is present in an amount of about 5% w/w to about 45% w/w, or about 10% w/w to about 40% w/w, of the amphetamine components in the composition. The extended release component and the immediate release amphetamine-cation exchange resin complex are further in combination with an uncomplexed amphetamine drug(s). The other immediate release component, which is an uncomplexed amphetamine drug, is present in an amount of about 5% w/w to about 25% w/w, or about 10⁰/ow/w to about 20% w/w of the amphetamine components in the compositions. In one embodiment, the weight percentages of amphetamine contributed by each of the two immediate release components are the same. However, in other embodiments, it may be desirable to provide amphetamine in the immediate release components in different weight percentages.

When expressed as a ratio based on the weight of free base amphetamine in each component: the ratio of the two immediate release components comprise amphetamine in a ratio of uncoated amphetamine-cation exchange resin complex (optionally in a matrix) to that in uncomplexed amphetamine in the chewable tablet is generally in the range of about (3 to 3.4):1 (uncoated amphetamine-cation exchange resin complex: uncomplexed amphetamine) to about 1:1 (uncoated amphetamine-cation exchange resin complex: uncomplexed amphetamine), or about 2.5:1 to about 1:1. In one embodiment, the ratio of modified release coated amphetamine-cation exchange resin complex to uncoated amphetamine-cation exchange resin complex is in the range of about 7:3.5 (coated amphetamine-cation exchange resin: uncoated amphetamine-cation exchange resin complex) or about 7:1 to about 2:1 (coated amphetamine-cation exchange resin complex: uncoated amphetamine-cation exchange complex), or about 5:1 to about 3:1, or about 5:3, or about 3.2:1.

In one embodiment, a composition contains a ratio of amphetamine in a coated amphetamine-cation exchange resin complex: uncoated amphetamine-cation exchange resin complex: uncomplexed amphetamine is about 70:about 10:about 20. The uncomplexed amphetamine may be about 3:1 ratio of d-amphetamine to l-amphetamine or about 50% by weight (d,l)-amphetamine to 50% by weight d-amphetamine; thus, the ratio of amphetamine in this composition may also be represented as about 70:about 10:about 10:about 10. In one embodiment, the composition is a tablet having chewable and orally dissolving properties. Other suitable ratios, may be selected within the ranges provided herein.

In one embodiment, a composition contains a ratio of amphetamine in coated amphetamine-cation exchange resin complex:uncoated amphetamine-cation exchange resin complex:uncomplexed amphetamine is about 50 to about 60:about 30 to about 45:about 5 to about 20. The uncomplexed amphetamine may be about 3:1 ratio of d-amphetamine to l-amphetamine, optionally in the form of about 50% by weight (d,l)-amphetamine to 50% by weight d-amphetamine. In one embodiment, the composition is an aqueous oral suspension. Other suitable ratios, may be selected within the ranges provided herein.

An “amphetamine-cation exchange resin complex” refers to the product resulting from loading an amphetamine which has been disassociated with any counterion and bound to a cation exchange resin. Methods for preparing such complexes have been described, e.g., in WO 2007/109104, the disclosure of which is incorporated herein by reference. This describes the complexation which occurs when the active drug and the cation exchange resin are mixed together in an aqueous medium to facilitate the “exchange” between the salt of the amphetamine and the “cation” of the cation exchange resin and the formation of the complex, which may be referred to as “amphetamine polistirex”. WO 2007/109104 also describes polyvinylacetate-based barrier coatings which are particularly well suited for use in the formulations described herein to provide a modified release coat over the amphetamine-cation exchange resin complex-matrix. However, one skilled in the art can select other barrier coatings to provide the modified release characteristics to amphetamine-cation exchange resin complex-matrix. The term “amphetamine-cation exchange resin complex” and “amphetamine polistirex” are used interchangeably throughout this specification. Further, the term “amphetamine-cation exchange resin complex” or “amphetamine polistirex” includes when more than one form of an amphetamine is complexed to the same cation exchange resin, e.g., a cation exchange resin may have both racemic (d,l)-amphetamine and d-amphetamine complexed thereto.

As used herein, a “precoated” amphetamine-cation exchange resin complex or a “precoated” amphetamine-cation exchange resin complex-matrix refers to a particle which is to be subsequently coated with a barrier coating as defined herein. In some embodiments, where the amphetamine-cation exchange resin or amphetamine-cation exchange resin complex-matrix is to be used as one of the immediate release components and no barrier coating is to be applied, it is referred to as “uncoated”. In some embodiments, the “immediate release coated amphetamine-cation exchange resin complex” may have a selected coating thereon, where the coating does not confer any modified release to the amphetamine.

As used herein, a barrier coat is a water-permeable, water-insoluble, pH-independent polymer or co-polymer which in the present invention confers modified release to the coated amphetamine-cation exchange resin complex-matrix. In one embodiment, the barrier coat is pH-independent, non-ionic and is applied, e.g., as an aqueous suspension, over the precoated amphetamine-cation exchange resin complex-matrix and forms a separate layer thereon. In another embodiment, the barrier coat is pH-independent, non-ionic and is applied as a solvent-based coating, over the amphetamine-cation exchange resin complex-matrix and forms a separate layer thereon. In still another embodiment, the barrier coat is pH-independent, ionic and is applied over the amphetamine-cation exchange resin complex-matrix to form a separate layer thereon. Preferably, the barrier coat is directly over the amphetamine-cation exchange resin complex-matrix and the barrier coat layer, i.e., there are no intervening layers between the barrier coat and the amphetamine-cation exchange resin complex-matrix. Depending upon the polymeric material selected, the barrier coat polymer or co-polymer may be cured to maximize its properties. These polymers and their curing requirements are discussed in more detail elsewhere in this specification.

An “amphetamine-cation exchange resin complex-matrix” refers to an amphetamine-cation exchange resin complex which is further combined, e.g., prior to or during granulation, with a polymeric material which forms a matrix with the amphetamine-cation exchange resin complex.

The term “matrix forming polymer” or “matrix forming polymeric material” refers to both water-insoluble (hydrophobic) polymers and co-polymers and water-soluble (hydrophilic) polymers and co-polymers which form a matrix with the amphetamine-cation exchange resin complex upon being admixed or granulated therewith. Suitably, the matrix forming polymer is non-reactive with the AMP and the cation exchange resin. The matrix forming polymer may be a water-insoluble polymers/co-polymers and polymer systems which have been described as release retardants [see. e.g., polymers discussed in U.S. Pat. No. 8,062,677, the disclosure of which is incorporated herein by reference], and those hydrophilic polymer systems which have been described in the literature as impregnating or solvating agents [see. e.g., polymers discussed in U.S. Pat. Nos. 8,062,677 and 4,221,778, incorporated herein by reference]. In one embodiment, an amphetamine-cation exchange resin complex-matrix may include more than one matrix-forming polymer system. For example, an amphetamine-cation exchange resin complex-matrix may contain both a hydrophilic polymer and a hydrophobic polymer. An immediate release “uncoated amphetamine-cation exchange resin complex” may optionally be in a matrix. In this instance, the matrix forming polymer does not substantially alter the ability of the amphetamine-cation exchange resin complex-matrix to provide an immediate release profile. For example, a polyvinylpyrrolidone may be selected as a matrix forming polymer. Alternatively, the matrix forming polymer may alter the release rate of this complex while still maintaining an immediate release profile as defined herein.

The following terms are used in the specification and are to be interpreted in accordance with the definitions herein.

“C_(max)” is the maximum observed plasma concentration, calculated as the geometric mean of the individual maximum blood plasma concentrations.

The term “mean maximum plasma concentration” (mean C_(max)) is defined for the purposes of the present invention as the maximum mean plasma drug concentration.

“Mean plasma concentration” is the arithmetic mean blood plasma concentration.

The term “T_(max)” is the time at which the peak (maximum) observed blood plasma drug concentration for each individual participating in the bioavailability study.

The term “AUC_(0-∞)” or “AUC_(inf)” is the mean area under the plasma concentration-time curve extrapolated to infinity. It is calculated as the mean of the area under the plasma concentration-time curve from time 0 extrapolated to infinity, calculated for each individual participating in the bioavailability study and may be the geometric or arithmetic mean. Partial AUC may be useful in determining bioequivalence, where the AUC is determined based on a specific fragment of the AUC_(0-∞). These fragments may be, e.g., from 0-4 hours, 5-8 hours, 9-13 hours, or at 0-4, 4-8, 8-12, 8-13, under fasting and/or fed conditions, or at different intervals, including those where t is 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, or up to 24 hours as end time points.

In one embodiment, a composition of the invention has no food effect, i.e. there is no statistical difference in one or more of the pharmacokinetic parameters, including, e.g., C_(max), AUC_(0-∞)”, and/or one or more partial AUCs, when patients are administered a dose under fasted conditions as compared to fed conditions.

AUC_(0-t) is the area under the plasma/serum/blood concentration-time curve from time zero to time t, where t is the last time point with measurable concentration for individual formulation.

“Bioequivalent” means the pharmacokinetic profile of a test composition is within the range of about 80% to about 125%, when compared to the values of one or more of the AUC values or the C. of the reference composition.

As used herein, the term “equivalent” to amphetamine free base is used to refer to the weight of the amphetamine portion of the amphetamine salt (e.g., a racemic, d-amphetamine or l-amphetamine) without the counterion, or the amphetamine portion of a drug-ion exchange resin complex, without taking into account the weight of the cation exchange resin or any matrix or coating component.

When reference is made to “different amphetamines”, it will be understood that a racemic amphetamine, a d-amphetamine, and an l-amphetamine are considered herein to be “different” from one another. As a whole, they may be considered “amphetamines”. Similarly, the other types of amphetamines or amphetamine derivatives as defined herein are encompassed by this definition. In some circumstances, counterions which form salts with these free bases are referred to as “different counterions”. This will be readily understood to refer to the counterions of a different free radical which is capable of forming a pharmaceutically acceptable salt with an amphetamine free base.

The term “half-life” is the apparent terminal elimination half-life (T_(1/2)).

The words “comprise”, “comprises”, and “comprising”, and “contain”, “containing”, and “contains” are to be interpreted inclusively rather than exclusively. The words “consist”, “consisting”, and its variants, are to be interpreted exclusively, rather than inclusively.

As used herein the term “about” means a variability of 10% from the reference given, unless otherwise specified.

Amphetamine-Cation Exchange Resin Complexes

As described herein, a polistirex or drug-cation exchange resin may contain one form of an amphetamine, e.g., racemic (d,l) amphetamine, or two or more amphetamine compounds. An amphetamine can be complexed with, or loaded onto, a cation exchange resin, using methods which are known in the art. See. e.g., WO 2007/109104, the disclosure of which is incorporated by reference, and the documents cited therein. One or more different amphetamine compounds [e.g., racemic, d-, or l-amphetamine] may be synthesized or obtained from commercial sources as described above.

Cationic exchange resins are readily selected for use as described herein. For example, cationic exchange resins vary in strength, i.e., in their ability to exchange cations. In one embodiment, a relatively strong cationic resin, e.g., Amberlite® IRP69, manufactured by Dow Chemical (a sulfonated copolymer of styrene and divinylbenzene) is selected. Alternatively, one may select a relatively weak cationic exchange resin, e.g., Amberlite® IRP88 [Dow Chemical (which acquired previous manufacturer Rohm & Haas) a crosslinked polymer of methacrylic acid and divinylbenzene)], a weakly acidic (potassium ion) cation exchange resin with 4% cross-linked methacrylate (100 to 500 mesh, equivalent to about 150 microns to about 27 microns, ASTM standard) or Amberlite® IRP64 (a methacrylic acid and divinylbenzene polymer (hydrogen ion) polacrilex resin, Rohm and Haas, with a particle size ranging from 100 to 400 mesh (equiv to 35 microns to 150 microns, ASTM standard size), capacity ˜10 meq/g by dry weight). Further, either regularly or irregularly shaped particles may be used as cation exchange resins according to the present invention. Regularly shaped particles are those particles that substantially conform to geometric shapes such as spherical, elliptical, cylindrical and the like, which are exemplified by Dowex® 50WX8 (The Dow Chemical Company). Irregularly shaped particles are all particles not considered to be regularly shaped, such as particles with amorphous shapes and particles with increased surface areas due to surface channels or distortions. Irregularly shaped ion-exchange resins of this type are exemplified by Amberlite® IRP-69 (manufactured by Dow Chemical), the use of which is illustrated in the examples below. This cation exchange resin is a sulfonated polymer composed of polystyrene cross-linked with about 8% of divinylbenzene, with an ion-exchange capacity of about 4.5 to 5.5 meq/g of dry resin (H*-form). Another cation exchange resin having similar properties is Dowex® 50WX8 (H+ form, linear formula, C₁₀H₁₂.C₁₀H₁₀.C₈H₈)_(x), 200-400 mesh particle size, which is equivalent to about 75 microns to about 35 microns, ASTM standard). Amberlite® IRP-69 consists of irregularly shaped particles with a size range of about 100 to about 500 mesh (about 150 microns to about 27 microns, ASTM standard). Dowex® 50WX8 is more regularly shaped. Resins are generally purchased with a size ranging from about 25 microns to about 400 microns. However, other sizes may be selected, or larger sized particles may be milled to provide smaller particle sizes.

The selected ion-exchange resins may be further treated by the manufacturer or the purchaser to maximize the safety for pharmaceutical use or for improved performance of the compositions. Impurities present in the resins may be removed or neutralized by the use of common chelating agents, anti-oxidants, preservatives such as disodium edetate, sodium bisulfite, sodium metabisulfite, and so on by incorporating them at any stage of preparation either before complexation or during complexation or thereafter. These impurities along with their chelating agent to which they become bound may be removed before further use of the cation exchange resin.

A method for preparing a drug-cation exchange resin complex involves reacting the drug(s) and cation exchange resin in water under conditions which permit formation of a complex. Typically, the reaction step involves combining the active drug(s) or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable, water-insoluble, cation exchange resin in an aqueous admixture and mixing for a sufficient amount of time to allow binding of the drug free base to the cation exchange resin. Optionally, a single amphetamine drug may be used in the following methods in a single complexing (loading) step to form an amphetamine-cation exchange resin complex containing a single amphetamine drug (e.g., d-amphetamine). These steps may be repeated in separate processes for the other amphetamine-cation exchange resin complexes to be used in a composition of the invention. Alternatively, a mixture of amphetamine drugs may be used in a single complexing step to provide an amphetamine-cation exchange resin complex which contains a mixture of amphetamine drugs (e.g., (d,l)-amphetamine, d-amphetamine, and/or l-amphetamine). Mixing during the complexing step may be, e.g., for about 1 hour to about 5 hours, followed by further processing which may take up to about 72 hours or longer. Suitably, the aqueous complexation suspension has a moisture content in excess of 50% w/w, more typically in the range of about 60% to about 90% w/w. Thereafter, moisture is removed by filtering of the aqueous reaction media to remove the bulk of the water remaining in the filter cake and thereafter optionally heating the filter cake containing the drug-cation exchange resin complex to remove additional water remaining in the filter cake after filtration is complete. During this processing, all or substantially any remaining counter-ion of the starting pharmaceutically active salt of the drug is removed through the washing steps.

The order of admixing in the complexation step; the drug(s) and the cation exchange resin may be performed in multiple ways. Optionally, a cation exchange resin for preparing a complex may be pre-washed, e.g., according to its manufacturer's instructions or as previously described. See. e.g., U.S. Pat. No. 8,062,667, the disclosure of which is incorporated by reference herein.

As described above, the reaction between the drug (e.g., (d,l)-amphetamine and/or d-amphetamine) and cation exchange resin occurs in a suspension having a water content in excess of 50% w/w, more typically in the range of about 60% to about 90% w/w to facilitate complexing of the amphetamine with the cation exchange resin. While the moisture content may be provided by water alone, optionally, solvents in addition to water may be present in this aqueous reaction slurry. For example, suitable solvents may include isopropyl alcohol, methanol or ethanol, or mixtures thereof in the aqueous slurry. In certain embodiments, the moisture content of the slurry may be reduced to below about 50% w/w, and more desirably, in the range of about 20% w/w to about 30% w/wand/or, more preferably 2 to 10% w/w. The total amount of amphetamine that can be complexed with a resin will typically range from about 5% to about 50% by weight of the amphetamine-cation exchange resin complex particles. A skilled artisan with limited experimentation can determine the optimum loading for any amphetamine-cation exchange resin complex. In one embodiment, loading of about 10% to about 40% by weight, more desirably, about 15% to about 30% by weight, or about 25% of the amphetamine-cation exchange resin complex particles can be employed. In one embodiment, a composition of the invention contains amphetamine complexed to a sodium polystyrene sulfonate resin in at a ratio of 20 parts amphetamine (based on the weight of the amphetamine salt) to 300 parts cation exchange resin or 80 parts amphetamine (based on the weight of the amphetamine salt) to 100 parts cation exchange resin. In another embodiment, the amphetamine (based on the weight of the amphetamine salt) to resin ratio is 4:1 to 1:15, or 4:1 to about 1:4, or about 1:1. Ina further embodiment, the amphetamine-cation exchange resin may contain more than one amphetamine compound bound to the same cation exchange resin, e.g., (d)-amphetamine and d-amphetamine. In certain embodiments, both the modified release component and the immediate release amphetamine-cation exchange resin complex contain two different amphetamines bound to the same cation exchange resin complex. In another embodiment, one of the immediate release components contains a blend of amphetamine-cation exchange resin complexes, in which a (d,l)-amphetamine-cation resin complex and a d-amphetamine-cation exchange resin complex are blended or admixed. In another embodiment, the modified release component contains a blend of barrier coated amphetamine-cation exchange resin complex-(optional matrix), in which a modified release, barrier coated (d,l)-amphetamine-cation exchange resin complex and a modified release, barrier coated d-amphetamine-cation exchange resin complex are blended or admixed to provide the modified release component. In another embodiment, the modified release component contains a blend of barrier coated amphetamine-cation exchange resin complex-(optional matrix), in which a modified release, barrier coated d-amphetamine-cation resin complex and a modified release, barrier coated l-amphetamine-cation resin complex are blended or admixed to provide the modified release component. In yet another embodiment, the immediate release component includes an uncoated d-amphetamine-cation exchange resin complex and an uncoated l-amphetamine-cation exchange resin complex blended or admixed. In such an instance, the blend may comprise about 3.2% by weight d-amphetamine to about 1% by weight l-amphetamine, which weight percent is based on the weight of the amphetamine without calculating the weight contribution of the other components of the complex (e.g., ion exchange resin, or any matrix or coating polymer present). Following the complexation reaction, an amphetamine-cation exchange resin complex may be, in no particular order, milled to achieve a desired size range and dried (e.g., to a moisture content below about 10%, e.g., about 3% to about 7⁰/), and then stored for future use. In one embodiment, the complex is milled or passed through a sieve to provide a particle size ranging from about 40 microns to about 410 microns to enhance mouth feel (i.e., texture), or about 50 microns to about 250 microns. These particles may be either regularly or irregularly shaped. In some embodiments, the average particle size of the uncoated amphetamine-cation exchange resin complex or the average particle size of the coated amphetamine-cation exchange resin complex is milled to a size of about 100 to about 200 microns. These particle sizes maybe determined using sieve analysis through a sieve shaker having USP standard wire mesh sieves conforming to ASTM specifications.

In another embodiment, rather than drying for storage, a sufficient amount of water is removed from the wet mass containing the formed complex (i.e., the slurry in which the reaction occurred) to optimize uniform application of a granulating agent, followed by further removal of moisture. Typically, the washing steps, filtration, and/or other steps for removal of moisture result in removal of substantially all of counter-ions from the drug-cation exchange resin complex.

A number of the processing steps described herein, including, e.g., loading, pre-washing, complexing and granulation may be carried out in a multi-purpose apparatus, e.g., such as the AFD450 processor [Pall SeitzSchenk] or another similar and larger scale multi-purpose apparatus which is available commercially [e.g., by Rosenmund, U.S. Pat. No. 5,609,835]. The vessel is capable of or adapted for pivoting and has a single chamber with the capacity for handling a reaction/crystallization, filtration, resuspension, and drying. Such a vessel is typically provided with a water jacket connected with a thermostatically controlled heating and cooling system. Alternatively, this vessel is used for only a single processing step in conjunction with multiple different apparatus, including, e.g., granulators (e.g., the GMX-75 high shear granulator), a dryer, and others which are known in the art.

In one embodiment, a matrix forming polymer is combined with the amphetamine-cation exchange resin complex following only partial complexation, or by reducing the moisture content of the wet amphetamine-cation exchange resin complex to a range of between about 15 to about 25%, or another suitable amount. Treatment of the amphetamine-cation exchange resin complex with the matrix forming polymer is as follows.

Amphetamine-Cation Exchange Resin Complex-Matrix

Optionally, a matrix-forming polymer is used to assist in processing an uncoated or precoated amphetamine-cation exchange resin complex. For example, a matrix-forming polymer may be used to facilitate granulation of the immediate release amphetamine-cation exchange resin complex, or as desired, e.g., in preparation for coating of an uncoated amphetamine-cation exchange resin complex.

In one embodiment, a polyvinylpyrrolidone polymer [e.g., such as may be purchased commercially as KOLLIDON® 30] is combined with the amphetamine-cation exchange resin complex in order to facilitate granulation prior to coating. Other hydrophilic polymeric granulating agents may include water-soluble polymeric materials which have been described in the art as impregnating agents or solvating agents and which function in the present application as granulating agents. In one embodiment, the granulating agent is a polyethylene glycol. Examples of desirable impregnating/solvating agents include those described in US Published Patent Application 2007/0215511, Sep. 20, 2007, and US 2003/0099711, which are incorporated herein by reference, or in U.S. Pat. No. 4,221,778 and published US Patent application Publication No. US 2003/0099711, the disclosures of which are incorporated herein by reference. Specific examples of other impregnating agents include propylene glycol, polyethylene glycol, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose, and sorbitol.

Optionally, the amphetamine-cation exchange resin complexes of the present invention may be admixed or granulated with a water-soluble or water-insoluble polymer or a combination of a water-insoluble polymers prior to the application of the water-permeable diffusion barrier coating described herein. Upon admixture, these polymers do not form a separate layer on the amphetamine-cation exchange resin complex. These polymers form a matrix therewith. Examples of suitable matrix forming polymers include, for example, a polyvinyl acetate polymer or a mixture of polymers containing same (e.g., KOLLICOAT® SR 30D), cellulose acetates, ethylcellulose polymers (e.g., AQUACOAT™ ECD-30 or SURELEASE™), acrylic based polymers or copolymers (e.g., represented by the EUDRAGIT® polymer family of acrylic resins), cellulose phthalate, or any combination of such water-insoluble polymers or polymer systems. These matrix-forming polymers when used may further prolong or alter the release of the amphetamine from the cation exchange resin complex/matrix and maximize attaining the desired release profile. One suitable polymer is a polyvinyl acetate polymer as described herein or an acrylic polymer from the EUDRAGIT® family. Examples of suitable acrylic polymers from the EUDRAGIT® family may include, e.g., a copolymer comprising ethyl acrylate and methyl methacrylate (e.g., EUDRAGIT® NE-30D), or EUDRAGIT® RS30D, RL30D, which are largely pH-independent polymers. EUDRAGIT® RS30D is a 30% aqueous dispersion of poly (ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride) in a ratio of 1:2:0.1; other aqueous dispersions of this copolymer may be selected. Eudragit® RL30 D is a 30% aqueous dispersion of poly (ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride) 1:2:0.2; other aqueous dispersions of this copolymer may be selected for use in the invention. Although less desirable, certain pH-dependent (enteric) polymers including, e.g., members of the EUDRAGIT polymer family, e.g., the L, S, and E, polymers and others which are commercially available may be selected.

The quantity of matrix forming polymer in an amphetamine-cation exchange resin complex-matrix typically ranges from about 1% to about 30%, or about 3 to about 20%, or about 3 to about 10%, about 10% to about 15%, about 15 to 25%, or about 5% or more by weight of the uncoated or amphetamine-cation exchange resin particulates prior to their being optionally coated. However, higher or lower amounts may be selected. In one embodiment, where it is desired for the matrix forming polymer to have little or no effect on release rate, a hydrophilic polymer may be selected and used in a higher amount, whereas a hydrophobic release retardant if selected for use will be used at a lower amount. Following admixing, the amphetamine-cation exchange resin complex particles with the matrix forming polymer, the mixture is dried and the amphetamine-cation exchange resin complex-matrix granules are milled appropriately to the desired particulate size.

For the amphetamine-cation exchange resin complex-matrix which will be coated and the uncoated amphetamine-cation exchange resin complex, the particles are milled though a size below about 420 microns, or generally in the range of about 50 microns to about 420 microns, or about 100 microns to about 420 microns. This can be achieved, e.g., using a CO-MIL device fitted with a 40 mesh screen. In one embodiment, the particles have an average size of about 100 to about 250 microns, or about 100 to about 200 microns. In some cases, the milling may be carried out before the complete drying of the complex or complex matrix and then again further drying followed by milling to obtain the desired complex characteristics. These particle sizes maybe determined using sieve analysis through a sieve shaker having USP standard wire mesh sieves conforming to ASTM specifications.

Barrier Coat for Modified Release

The modified release component of an amphetamine-cation exchange resin complex-matrix with a barrier coating which modifies the release profile of the active amphetamine(s) such that the amphetamine has at least about a modified release profile. Suitably, the barrier coating has a pH-independent release (i.e., it is not an enteric coating which has pH-dependent release) and is a water-insoluble, water-permeable coating material. In a preferred embodiment, neither the liquid suspension, chewable tablet nor any of its components has an enteric or other pH-dependent coating.

Suitably the properties of the barrier coating provide modified release properties to the barrier coated amphetamine-cation exchange resin complex, which is amphetamine-cation exchange resin is optionally in matrix. When the matrix is present, the barrier coating is applied over the amphetamine-cation exchange resin complex-matrix. The barrier coating provides the modified release component with resistance to grinding forces which enables the portions of a chewable tablet of the invention to provide a modified release amphetamine profile even when cut into pieces.

In one embodiment, the barrier coating has a characteristic high flexibility or elongation (elasticity) at break measured by the texture analyzer TA-XT2 HiR (Stable Microsystems) and by the method reported by the manufacturer in its literature [i.e., Jan-Peter Mittwollen, Evaluation of the Mechanical Behavior of Different Sustained Release Polymers, Business Briefing: Pharmagenerics, 2003, pp. 1-3, BASF], with a tensile strength in a range of at least about 150% to about 400%. When the polyvinylacetate based barrier coating described herein is selected, this is achieved while not substantially increasing the tackiness of the polymer film greater than about 2 (wherein the film is measured by the Hössel method independent of any composition on which it has been deposited) P. Hossel, Cosmetics and Toiletries, 111 (8) 73 (1996).

In one embodiment, the barrier coating layer is about 10% to about 55%, by weight, or about 10% to about 50%, by weight, of the amphetamine-cation exchange resin complex-optional matrix in order to provide the modified release component. In another embodiment, the barrier coating layer is about 20% to about 40%, about 25% to about 35% by weight, or about 30%, by weight of the amphetamine-cation exchange resin complex-matrix (i.e., prior to coating). Still other suitable ranges can be determined by one of skill in the art, having been provided with the information herein.

The barrier coating is applied over the uncoated amphetamine-cation exchange complex-optional matrix (e.g., as an aqueous dispersion or a solution), dried, and milled or passed through a screen such that the barrier coated amphetamine-cation exchange complex-optional matrix particles are in the same size range as described in the preceding paragraph, i.e. an average of about 100 microns to about 300 microns, or an average of about 150 microns to about 250 microns.

In one embodiment, the barrier coating is applied as an aqueous dispersion which is dried in order to provide the desired modified release profile. In the case of an aqueous-based polyvinylacetate coating, the coating is cured in order to provide the desired release profile.

In one embodiment, the barrier coating is applied as an aqueous dispersion of a water insoluble polymer comprising a polyvinyl acetate polymer, or a blend of polymers comprising a polyvinyl acetate polymer. In one embodiment, the barrier coating further contains a plasticizer, which can facilitate uniform coating of the amphetamine-cation exchange resin complex-optional matrix and enhances the tensile strength of the barrier coating layer.

One coating composition useful in the present invention is applied in the form of an aqueous dispersion containing polyvinylacetate (PVA) polymer based aqueous coating dispersion and a plasticizer. The PVA is insoluble in water at room temperature. The PVA may be used in either substantially pure form or as a blend. Where the barrier coating comprises a PVA polymer, the PVA polymer is present in an amount of about 70% to about 90% w/w of the final barrier coating layer, at least about 75%, at least about 80%, about 85% w/w of the final barrier coating layer. Generally, a plasticizer is used in the percent range, or a mixture of plasticizers combine to total about 2 to about 50% by weight of the coating layer, more preferably about 2.5% to about 20% by weight of the coating layer on the coated amphetamine-cation exchange resin complex. Preferably a plasticizer is in a range of about 2.5 to about 15% by weight of the coating layer based on the coated complex provides the most desirable properties. Suitable plasticizers may be water soluble and water insoluble. Examples of suitable plasticizers include, e.g., dibutyl sebacate, propylene glycol, polyethylene glycol, polyvinyl alcohol, triethyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, tributyl citrate, triacetin, and Soluphor® P (2-pyrrolidone), and mixtures thereof. Other plasticizers are described in patent application publication US 2003/0099711 A1, May 29, 2003, page 4 (0041) the disclosure of which is incorporated herein by reference.

A commercial polyvinylacetate blend contains primarily a polyvinylacetate polymer, a stabilizer, and minor amounts of a surfactant such as sodium lauryl sulfate. Where the barrier coating comprises PVP as the stabilizer component, the final barrier coating layer generally contains about 5 to about 10% w/w of polyvinyl pyrrolidone. In one desired embodiment, the aqueous based barrier coating solution is KOLLICOAT® SR 30 D (BASF Corporation) and whose composition is about 27% PVA polymer, about 2.7% polyvinylpyrrolidone (PVP), about 0.3% sodium lauryl sulfate (solids content 30% w/w), mixed with a plasticizer. See, also, U.S. Pat. Nos. 6,066,334 and 6,026,277, which is incorporated by reference herein. The PVP and surfactant help stabilize the aqueous dispersion of the PVA. Generally, such stabilizing components are present in an amount totaling less than about 10% w/w, and preferably less than about 5% w/w. Optionally, a selected surfactant is present in an amount of about 1% or less. In one embodiment, the surfactant is a non-ionic surfactant. Optionally, an ionic surfactant may be selected.

In a particularly desirable embodiment, the desired modified release is obtained when the coating layer formed by application of the aqueous dispersion containing the KOLLICOAT® SR-30D-plasticizer is dried and cured. Preferably, the coating is cured for about 1 to about 24 hours. In alternate embodiments, the coating is cured for about 4 to about 16 hours, and preferably about 5 hours at high temperature, e.g., about 50° C. to about 65° C., and preferably about 60° C. Thus, in one embodiment, the coated amphetamine-cation exchange resin complex-matrix has a cured water-permeable, high tensile strength, water insoluble, barrier coating comprising a non-ionic polymer and a plasticizer and having an elongation factor in the range of about 150% to 400% over the amphetamine-cation exchange resin complex-matrix. In one embodiment, the barrier coating comprises a polyvinylacetate polymer, a stabilizer, a surfactant and a plasticizer. In one embodiment, a barrier coating comprises about 2.5 to about 15% of plasticizer, about 70 to about 90% polyvinylacetate, about 5 to about 10% polyvinylpyrrolidone, and about 0.1 to about 1% surfactant. See. e.g., US Published Patent Application No. US 2007/0215511A, published Sep. 20, 2007, and its counterpart application, WO 2007/109104, the disclosures of which are incorporated herein by reference.

It may be possible utilize other aqueous or non-aqueous solvent based systems which do not require curing. For example, an aqueous based acrylic polymer (a EUDRAGIT® RL30D and EUDRAGIT® RS30D blend is described herein), but requires the addition of anti-tacking agent such as, e.g., talc or glycerol monostearate (GMS), in order to facilitate processing and even coating.

In one embodiment, the coating may be a EUDRAGIT® brand acrylate based coating materials [including, e.g., a poly (ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride) polymer system]. For example, EUDRAGIT® RS 30D [a pH-independent, 30% aqueous dispersion of poly (ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride) 1:2:0.1)], or EUDRAGIT® RL 30D [a 30% aqueous dispersion, pH independent polymer, poly (ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride) 1:2:0.2)] may be selected as the barrier coating. In one embodiment, a blend of EUDRAGIT® RS 30D and EUDRAGIT® RL 30D may be prepared to optimize the hydrophilicity/hydrophobicity of the film in order to achieve desirable release profiles.

Suitably, a plasticizer may be included in the coating layer. In one embodiment, the barrier coating comprises about 2.5 to about 15% of plasticizer. Individual or a combination of hydrophilic or lipophilic plasticizers with a dispersion or suspension containing the barrier coating polymer. Such plasticizers include, e.g., propylene glycol, polyethylene glycol, triacetin, triethyl citrate, dibutyl sebacate, vegetable oil, lipids, etc. Optionally, a suitable anti-tacking agent may be mixed with one of the EUDRAGIT® products to improve flow during coating and to address issues of tackiness of the product during processing. Suitable anti-tacking agents include, e.g., talc, glycerol monostearate (GMS), and mixtures thereof. Suitably, these agents are present in an amount of about 0.2%-4.5% w/w based on the dry weight of the coating polymer applied to form the coating layer of the modified release component. Typically, the coating layer resulting from application of the blend described in this paragraph is not subject to any curing.

Optionally, another barrier coating may be selected. In another embodiment, a non-aqueous solvent-based ethylcellulose, such as commercially available as the ETHOCEL™ products (Dow) may be modified in order to achieve the barrier coating characteristics defined herein, e.g., by addition of a sufficient amount of plasticizer to improve flexibility and/or by curing to a sufficient temperature to achieve the desired release rate. Dow's web site describes three of these products, Std 7 (viscosity of 6-8 mPa-s (CP); Std 10 (9-11 mPa-s (CP)); Std 20 (18-22 mPa-S), each of which has a 48.0-49.5% ethoxyl content) as being useful for tablet coating. Further, optionally combining one of these polymers in combination with a water-soluble active and/or water-soluble excipient such as a METHOCEL™ cellulose ether and/or CARBOWAX™ polyethylene glycols is further described. Alternatively, it may be possible to modify an aqueous based ethylcellulose barrier coating in order to achieve the modified release barrier coating characteristics required herein, e.g., by addition of a sufficient amount of plasticizer to improve flexibility and/or by curing to a sufficient temperature to achieve the desired release rate. See, e.g., the barrier coatings described in U.S. Pat. Nos. 6,066,334 and 6,046,277; see, also, e.g., U.S. Pat. Nos. 6,046,277 and 6,001,392; US Published Patent Application No. 2003/0099711 and related application WO 03/020242; WO 2006/022996 and related applications US Published Patent Application Nos. US 2005/0232986; US 2005/0232987; US 2005/0232993; US 2005/0266032; U.S. Pat. Nos. 7,067,116; 6,667,058, 6,001,392, the disclosures of which are incorporated herein by reference, among others.

A coating as described herein may be applied using techniques described by the polymer manufacturer and/or techniques which are known to those of skill in the art. Suitable methods and apparatus have been described in the patent and non-patent literature and include, e.g., spraying in a fluid bed processor. The coating solution can be sprayed in a fluid bed processor (e.g., VECTOR™ FLM-1 fluid bed processor) using Wurster process. The coated amphetamine-cation exchange resin complex-(optional matrix) is then dried and/or cured. The dried, optionally cured, coated amphetamine-cation exchange resin complex-optional matrix may be passed through a suitable screen in order to ensure that the particle size is in the desired range, e.g., capable of passing through a standard 40 mesh screen. In one embodiment, the dried, optionally cured, coated amphetamine cation exchange resin complex (optional matrix) granules have an mean particle size in the range of about 100 microns to about 420 microns, or about 75 microns to about 250 microns, about 150 to about 300 microns. In one embodiment, less than 10% of the coated particles are under 75 microns in size.

Finished Dose Formulations

The compositions described herein include amphetamine oral suspensions and extended release chewable tablets. These compositions are orally administrable and readily titratable. The tablets maintain their extended release profile even when subject to chewing or division (e.g., splitting).

The one or more modified release barrier coated amphetamine-cation exchange resin complex-optional matrix, one or more uncoated amphetamine-cation resin complex and the one or more uncomplexed amphetamine may be prepared as described herein and blended together prior to combination with the excipients for formulation into a final suspension or chewable tablet formulation. Optionally, one or more of these components are prepared and dried (e.g., in powder form), either separately or together, for storage prior to formulation. Alternatively, the one or more modified release barrier coated amphetamine-cation exchange resin complex-optional matrix, one or more uncoated amphetamine-cation resin complex and the one or more uncomplexed amphetamine may be prepared separately as described above, and combined in any suitable order with the excipients present in the aqueous suspension base and/or the chewable tablet.

A Final Suspension

In one embodiment, the finished formulation (i.e., pharmaceutical composition) is a liquid suspension which is formed by mixing a liquid suspension base with the (coated or uncoated) drug-cation exchange resin complex-(optional matrix) to provide a finished liquid orally ingestible and effective formulation.

The liquid suspension may be formed in situ, e.g., by adding a placebo suspension base to the aqueous complexation reaction media (prior to or without filtration), e.g., of the slurry in which the uncoated drug-ion exchange resin complex is prepared. In another embodiment, one or more drug-cation exchange resin complex (coated or uncoated) is combined with one or more other components and admixed to prepare the final suspension base. See, e.g., U.S. Pat. No. 8,062,667. See, also, U.S. Pat. No. 8,329,224 B2 and Published Patent Application No. 2007-0148239, which describes multiple loadings onto a cation exchange resin; and WO 2007/001300, which generally describes drug loading and conjugating more than one active drug with a single resin particle, the disclosures of which are incorporated by reference herein. Additionally, methods useful for preparing liquid suspension combination products have been described where the drugs are in different forms may also be selected. See. e.g., U.S. Pat. Nos. 8,512,759, 8,062,667, and 8,329,224 B2.

A suspension or placebo base may also contain conventional pharmaceutically acceptable carriers or excipients. Without being limited to a suspension dosage form, suitable dosage forms may utilize conventional carriers or excipients including diluents, binders and adhesives (i.e., cellulose derivatives and acrylic derivatives), vegetable oils, polyethylene glycols, talc, sodium lauryl sulfate, polyoxyethylene monostearate, thickeners, solubilizers, humectants, disintegrants, colorants, flavorings, stabilizing agents, flavorants, including sweeteners, and miscellaneous materials such as buffers and adsorbents in order to prepare a particular pharmaceutical composition. The stabilizing agents may include preservatives and anti-oxidants, amongst other components which will be readily apparent to one of ordinary skill in the art.

Suitable thickeners include, e.g., tragacanth; xanthan gum; bentonite; starch; acacia and lower alkyl ethers of cellulose (including the hydroxy and carboxy derivatives of the cellulose ethers). Examples of cellulose include, e.g., hydroxypropyl cellulose, hydroxypropyl methyl cellulose, sodium carboxy methylcellulose, microcrystalline cellulose (MCC), and MCC with sodium carboxyl methyl cellulose. In one embodiment, starch is used and incorporated in an amount of from about 0.1 to about 1.5% weight per volume (w/v) of the composition. Xanthan gum is used in the amount of from about 0.025 to about 0.5% w/v and preferably about 0.25% w/v. The compositions may include a humectant composition to give the liquid greater viscosity and stability. Suitable humectants useful in the finished formulations include glycerin, polyethylene glycol, propylene glycol and mixtures thereof.

The oral liquid suspensions may also comprise one or more surfactants in amounts of up to about 5.0% w/v and preferably from about 0.02 to about 3.0% w/v of the total formulation. The surfactants useful in the preparation of the finished compositions of the present invention are generally organic materials which aid in the stabilization and dispersion of the ingredients in aqueous systems for a suitable homogenous composition. In one embodiment, the surfactants are non-ionic surfactants such as poly(oxyethylene)(20) sorbitan monooleate and sorbitan monooleate. These are commercially known as TWEENS and SPANS and are produced in a wide variety of structures and molecular weights. Any one of a number of surfactants may be used. In one embodiment, the compound is from the group comprising polysorbate copolymers (sorbitan-mono-9-octadecenoate-poly(oxy-1,2-ethanediyl)). This compound also has the added function to keep any flavors and sweeteners homogeneously dissolved and dispersed in solution.

Suitable polysorbates include polysorbate 20, polysorbate 40, polysorbate 80 and mixtures thereof. Most preferably, polysorbate 80 is employed. The surfactant component will comprise from about 0.01 to about 2.0% w/v of the total composition and preferably will comprise about 0.1% w/v of the total weight of the composition.

A second emulsifier/surfactant useful in combination with polysorbates may be employed and is preferably a poloxamer such as Poloxamer 407. Poloxamer 407 a triblock copolymer consisting of a central hydrophobic block of polypropylene glycol flanked by two hydrophilic blocks of polyethylene glycol. The approximate lengths of the two PEG blocks is 101 repeat units while the approximate length of the propylene gycol block is 56 repeat units, has an HLB (hydrophilic/lipophilic balance) of about 22 and is sold under the trade name Pluoronic-127 (BASF). The two surfactants can be employed in substantially equivalent amounts. For example, the Poloxamer 407 and polysorbate 80 may each be employed together at levels of approximately from about 0.02 to about 4.0% w/v of the formulation.

Aqueous suspensions may be obtained by dispersing the drug-cation exchange resin complex compositions in a suitable aqueous vehicle, optionally with the addition of suitable viscosity enhancing agent(s) (e.g., cellulose derivatives, xanthan gum, etc). Non-aqueous suspensions may be obtained by dispersing the foregoing compositions in a suitable non-aqueous based vehicle, optionally with the addition of suitable viscosity enhancing agent(s) (e.g., hydrogenated edible fats, aluminum salt, etc.). Suitable non-aqueous vehicles include, for example, almond oil, arachis oil, soybean oil or fractionated vegetable oils such as fractionated coconut oil.

Although not essential, the final suspension may optionally contain preservatives. Suitable preservatives may include the paraben preservatives include, methyl, ethyl, propyl, and butyl paraben. Methyl and propyl paraben are most preferable. Both methyl and propyl paraben may be present in the formulation in a ratio of methyl paraben to propyl paraben of from about 2.5:1 to about 16:1, preferably 9:1. Methods for evaluating the efficacy of preservatives in pharmaceutical formulations are known to those skilled in the art. Still other preservatives and preservatives are known to those of skill in the art. See, e.g., US Patent Publication No. 2008/0118570, the disclosure of which is herein incorporated by reference.

In the instance where auxiliary sweeteners are utilized, sweeteners well known in the art, including both natural and artificial sweeteners, can be included. Thus, additional sweeteners may be chosen from the following non-limiting list: Water-soluble sweetening agents such as monosaccharides, disaccharides and polysaccharides such as xylose, ribose, glucose, mannose, galactose, fructose, high fructose corn syrup, dextrose, sucrose, sugar, maltose, partially hydrolyzed starch, or corn syrup solids and sugar alcohols such as sorbitol, xylitol, mannitol and mixtures thereof. In general, the amount of sweetener will vary with the desired amount of sweeteners selected for a particular liquid formulation.

In one embodiment, none of these water-soluble sweeteners or sugars are included. In another embodiment, only an artificial sweetener is included. The artificial sweeteners [e.g., sucralose, acesulfame K, and dipeptide based sweeteners] are used in amounts of about 0.005 to about 5.0% and most preferably about 0.01 to about 2.5% by weight per volume of the final liquid composition. Such artificial sweetener may be present in an amount of about 0.2% w/v. These amounts are ordinarily necessary to achieve a desired level of sweetness independent from the flavor level achieved from flavor oils.

Suitable flavorings include both natural and artificial flavors, and mints such as bubble gum, peppermint, menthol, artificial vanilla, cinnamon, various fruit flavors, both individual and mixed, essential oils (i.e. thymol, eucalyptol, menthol and methyl salicylate) and the like are contemplated. The amount of flavoring employed is normally a matter of preference subject to such factors as flavor type, individual flavor, and strength desired. Thus, the amount may be varied in order to obtain the result desired in the final product. Such variations are within the capabilities of those skilled in the art without the need for undue experimentation. The flavorings are generally utilized in amounts that will vary depending upon the individual flavor, and may, for example, range in amounts of about 0.01 to about 3% by weight per volume of the final composition weight.

In one embodiment, no colorants are present in the composition. In another embodiment, colorants such as titanium dioxide may be incorporated in amounts of up to about 1% by weight per volume, and preferably up to about 0.6% by weight per volume. Also, the colorants may include dyes suitable for food, drug and cosmetic applications, and known as D&C and F.D. & C. dyes, aluminum lake pigments, and the like. The materials acceptable for the foregoing spectrum of use are preferably water-soluble. Illustrative examples include indigoid dye, known as F.D. & C. Blue No. 2, which is the disodium salt of 5,5′indigotindisulfonic acid. Similarly, the dye known as F.D. & C. Green No. 1 comprises a triphenylmethane dye and is the monosodium salt of 4-[4-N-ethyl p-sulfobenzylamino)diphenyl-methylene]-[1-(N-ethyl-N-p-sulfoniumbenzyl)-2,5-cyclohexadienimine]. A full recitation of all F.D. & C. and D. & C. and their corresponding chemical structures may be found in the Kirk-Othmer Encyclopedia of Chemical Technology, in Volume 5, at pages 857-884, the disclosure on these pages is incorporated herein by reference.

Wetting agents also may be employed to facilitate the dispersion of any hydrophobic ingredients. The concentration of wetting agents in the composition should be selected to achieve optimum dispersion of the ingredient within the composition with the lowest feasible concentration of wetting agent. It should be appreciated that an excess concentration of wetting agent may cause the composition, as a suspension, to flocculate. Those skilled in the art are well versed in suitable empirical methods to determine the appropriate wetting agents and concentrations to achieve optimum dispersion and avoid flocculation. Suitable wetting agents are listed in the US Pharmacopoeia 38.

In one embodiment, an aqueous oral amphetamine extended release suspension contains a modified release component comprising (d,l) and d-amphetamine in an amount of about 1.25 mg/mL (about 0.065% w/v d- and about 0.06% w/v (d,l)-amphetamine) based on the amount of amphetamine/total amphetamine in the composition, a fast onset immediate release component comprising (d,l) and d-amphetamine in an amount of about 0.5 mg/ml (0.024% w/v d,l-amphetamine and 0.026% w/v d-amphetamine), and a slower onset immediate release component comprising (d,l) and d-amphetamine in an amount of 0.75 mg/mL (0.036% w/v d,l-amphetamine and 0.039% w/v d-amphetamine) bound to an ion exchange resin and uncoated.

In another embodiment, a suspension of the invention contains: a ratio of 3.2:1 d- to l-amphetamine in the modified release component and a ratio of about 3.2:1 d- to l-amphetamine in the slower release immediate release component. In a further embodiment, the suspension has a pH in the range of about 2.5 to about 4, or about 3.2. In another embodiment, the oral suspension has the following components:

Component % w/v % w/v Modified Release barrier coated about 0.8 to about About 1.14% (d,l) and d-AMP - cation 2%, about 1% to exchange resin complex - matrix about 1.2% (coated AMP polistirex - matrix) Immediate Release Uncoated about 0.3% to About 0.486% containing (d,l)- and d-AMP - about 0.6%, or cation exchange resin complex about 0.4% to about 0.5% Immediate release total About .03% to About 0.087% l- Uncomplexed AMP about 1% total amphetamine and AMP, about 0.06% d- about 0.05 to amphetamine about 0.09% d- amphetamine;

In one desirable embodiment, a titratable, extended release aqueous oral suspension of Example 1 and compositions bioequivalent thereto are encompassed by the invention.

The composition so prepared may be stored for future use.

B. Chewable Tablets

In one aspect the invention provides an amphetamine extended release chewable tablet, which is optionally also orally dissolving. As with the liquid suspension, following administration of a single dose of the oral amphetamine extended release chewable tablet, in some embodiments, a therapeutically effective amount of amphetamine is reached in less than about thirty minutes, and as soon as about twenty, ten, or fewer minutes, and the formulation provides an extended release therapeutically effective profile to at least about 12 hours, or about 13 hours, or up to about 18 hours.

Further, the chewable tablet may be scored, as dividing the tablet does not significantly modify the in vitro profile of the tablet portions resulting from split or other division of the intact tablet.

Further, because the amphetamine chewable tablet described herein retains its extended release properties even when scored, it can be divided into other suitable portions. This makes the chewable tablet readily titratable and convenient for physicians to reduce the dose for patients to introduce the drug in a smaller dose or incremental doses of medication for patients whose needs dictate such. This ability to divide the dose into portions allows physicians to take into consideration individual patient needs, including factors like age, body weight and individual response to the medication without the need for taking multiple doses over a twelve hour period of another product which offers only immediate release.

The amphetamine extended release chewable tablets are typically prepared as single uniform solid dispersion compressed into a chewable tablet. Suitably, the chewable tablet of the invention is a uniform solid dispersion which provides extended release properties even when scored such that when divided the separated tablet portions retain the extended release profile described herein. In one embodiment, the chewable tablet has a hardness of about 2.5 kilopond (kp) to about 20 kp or about 3 to about 15 kp. One (1) kilopond is one kilogram of force (kgf). Newtowns (N) are the SI unit of force and the SI standard for tablet hardness testing. 1 kilopond (kp) is equal to 9.80665 Newtons (N). Presented in Newton rounded to the nearest five, the chewable tablet has a hardness of about 45 N to about 245 N, about 75 N to about 200 N, or about 95 N to about 160 N. Optionally, the hardness may be dose proportional, with lower doses having lower hardness levels. For example, a 20 mg chewable tablet may have a hardness in the range of about 7 to about 14 kp (about 68 N to about 127 N), a 15 mg tablet may have a hardness in the range of about 3 to about 9 kp (about 29 N to about 88 N), and a 10 mg tablet may have a hardness in the range of about 3 kp to about 11 kp (about 29 N to about 108 N). In one embodiment, the hardness is determined following compression and prior to application of any color or other non-functional tablet coating as defined herein. In one embodiment, the tablet portions meet the USP Friability requirement. In one embodiment, the friability of both the intact tablet and the tablet portions are less than about 1.

A tablet of the invention is distinguished by being chewable and also being a rapid dissolve tablet or an orally dissolving tablet (ODT) that will dissolve in the mouth in less than 1 minute. An ODT has been defined as a solid dosage form containing medicinal substances that disintegrates rapidly, usually within a matter of seconds, when placed upon the tongue. In general, the total weight of the ODT is recommended not to exceed 500 mg. See, Guidance for Industry, Orally Disintegrating Tablets, US Department of Health and Human Services, Food and Drug Administration Center for Drug Evaluation and Research (CDER) December 2008. In one embodiment, the tablet provided herein is a unit dosage form which is about 375 mg to about 425 mg, or about 400 mg in total weight. In another embodiment, the tablet is a unit dosage form which is about 350 mg to about 375 mg, or about 360 mg in total weight. In a further embodiment, the tablet is a unit dosage form which is about 200 to about 250 mg, or about 240 mg in total weight.

In one embodiment, the excipients do not alter the modified release properties of the chewable tablet. The modified release profile is provided by the modified release barrier coated amphetamine-cation exchange resin complex-matrix component. The amphetamine components may be pre-blended in the desired ratio to one another prior to being admixed with the excipients, described below. Alternatively, each of the amphetamine components are added separately and blended with the excipients.

As described above in this specification, the modified release barrier coated amphetamine-cation exchange resin complex, optionally in a matrix is present in an amount of about 50% w/w to about 75% w/w of the amphetamine components in the composition. The two immediate release components combine to provide about 25% w/w to about 50% w/w, about 20% w/w to about 40% w/w, or about 25% w/w to about 35% w/w of the amphetamine in the composition. The uncoated amphetamine-cation exchange resin complex component is designed to be immediate release as defined herein, and as such, does not contain a coating in an amount which functions to slow down release (e.g., no functional amount of extended modified release barrier coating or enteric coat). Suitably, the slower onset immediate release amphetamine-cation exchange resin complex supplies about 5% w/w to about 25% w/w, or about 10% w/w to about 20% w/w, of the amphetamine in the chewable tablet. The extended release component and the immediate release uncoated amphetamine-cation exchange resin complex are further in combination with uncomplexed amphetamine drug(s).

The amphetamine extended release chewable tablets may be prepared using one or more of a filler, one or more disintegrant, one or more binder, one or more a buffering agent, one or more lubricant, one or more glidant, or blends of these components. Suitably, the tablets also include taste and/or mouth feel enhancers including, e.g., one or more of a sweetener, a flavorant, a gum, or blends of these components. Optionally, the tablet may also contain a non-functional coating.

As used herein, a “non-functional coating” refers to a coating which contributes no detectable modified release functions. The non-functional coating may be a polymer which may serve as a moisture barrier to preserve the integrity of the tablet during storage or to facilitate application of a color coating layer. Additionally or alternatively, the non-functional coating may provide a color coating layer or improve the “smoothness” or mouth feel of the tablet. In one embodiment, the non-functional coating may increase the hardness of the tablet somewhat without affecting the chewability thereof.

Throughout the specification, where weight percentages of excipients and the three active components are provided, the weight percentages are exclusive of any weight added by a non-functional coating. Weight percentages of these non-functional coatings, where present, are provided as weight added, in an amount of about 1% to about 20%, or about 2% to about 10%, or about 3% to about 5% weight added to the finished chewable tablet.

Typically, a chewable tablet will contain a filler or a mixture of fillers in the range of about 10% w/w to about 90% w/w, about 50% w/w to about 85% w/w, or about 50% w/w to about 70% w/w of the total tablet weight. Suitable fillers may include, e.g., mannitol, lactose, maltose, fructose, sucrose, xylitol, maltitol, microcrystalline cellulose, dicalcium phosphate, guargum, xanthan gum, tragacanth gum, pre-gelatinized starch, compressible sugar, calcium carbonate, magnesium carbonate, calcium sulfate, dextrates, maltodextrin. In one embodiment, a chewable tablet of the invention contains a blend of mannitol, xanthan gum, microcrystalline cellulose, and guar gum in an amount of about 60% w/w to about 75% w/w. In one embodiment, a gum or a combination of gums is provided in an amount of about 0.25% w/w to about 5% w/w, or about 0.25% to about 1% w/w. In another embodiment, microcrystalline cellulose is provided in an amount of about 5% w/w to about 25% w/w, or about 10% w/w to about 15% w/w based on the total tablet weight prior to any non-functional coating. A product containing a combination of microcrystalline cellulose and guar gum is commercially available as Avicel®, which contains a ratio of 80 parts by weight microcrystalline cellulose to 20 parts by weight guar gum. This blend of microcrystalline cellulose (MCC) and guar gum may be present in an amount of about 5% w/w to about 25% w/w of the total tablet weight.

A chewable tablet as described herein will also contain a disintegrant or blend of disintegrants in the range of about 1% w/w to about 25% w/w, or about 5% w/w to about 15% w/w, or about 10% w/w to about 14% w/w based on the total tablet weight. Suitable disintegrants include, e.g., crospovidone, sodium starch glycolate, croscarmellose sodium, carboxymethyl cellulose sodium, carboxymethylcellulose calcium, starch. In one embodiment, a tablet as described herein contains crospovidone in a range of about 5% w/w to about 10% w/w, or about 12% w/w based on the tablet weight prior to any non-functional coating being applied.

The binder for the chewable tablet may be absent (i.e., 0%), or optionally, present in an amount of about 1% w/w to about 15% w/w of the total tablet weight. Examples of suitable binders include polyvinylpyrrolidone (Povidone), hydroxypropyl methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, methyl cellulose, polyvinyl alcohol, starch, acacia, alginic acid, sodium alginate.

In one embodiment, the chewable tablet contains a sweetener in an amount of about 0.01% w/w to about 3% w/w, or about 0.5% w/w to about 2% w/w, or about 1% w/w to about 2% w/w or about 1.5% w/w, based on the total tablet weight exclusive of any optional non-functional coating. Suitable sweeteners may include, e.g., Aspartame, Saccharin, Saccharin sodium, Sucralose, Sodium cyclamate, Xylitol, Acesulfame Potassium, and blends thereof. Optionally, in addition to functioning as a sweetener, an excipient may function as a filler. Examples of suitable sweeteners/fillers including, e.g., fructose, sucrose, xylitol, maltitol. Optionally, when performing both functions, the excipient may be present in an amount in excess of about 10% w/w of the tablet. In such an instance, additional sweetener may be omitted (e.g., present in 0% added sweetener). Alternatively, a second sweetener or a combination of sweeteners which differs from the filler is added in the amount provided in this paragraph in order to further enhance taste.

Suitably, the tablet is provided with a buffering agent in an amount of about 0.1% w/w to about 5% w/w, or about 0.5% w/w to about 1.5% w/w based on the total tablet weight. Examples of suitable buffering agents include, e.g., citric acid, tartaric acid, malic acid, lactic acid, and acceptable salts thereof, and mixtures thereof. In one embodiment, the buffering agent adjust the pH of the tablet (if suspended in water) to a range of about 3.5 to about 5, or about 4 to about 4.5, or about 4.2. In one embodiment, the buffering agent is citric acid, which also provides desirable taste properties.

When an additional flavoring agent is added, the flavoring agent(s) may be added in an amount of about 0.05% w/w to about 3% w/w, or about 0.1% to about 1% w/w or about 0.5% w/w, based on the total weight of the tablet (exclusive of any optional non-functional coating). Suitable flavoring agents may include, both natural and artificial flavoring agents such as are generally available through several custom manufacturers around the world such as Fona [Illinois, US], Givaudan (Vernier, Switzerland), Ungerer & Company (Lincoln Park, N.J.), and International Flavors & Fragrances (New York, N.Y.) to name a few. Those skilled in the art will recognize that there are several commercial sources available including custom blenders. The flavorings may be blended prior to addition to the pharmaceutical composition or added separately. Still other flavoring agents such as bubble gum, cherry, strawberry, vanilla, grape, banana and other flavors or mixtures thereof may be selected.

Optionally, a colorant may be provided to the tablet to provide a desired visual appeal or trade dress. Such colorants may be added in the range of about 0.001 to about 1% w/w, or about 0.01% w/w to about 0.08% w/w or about 0.05% w/w, based on the total weight of the tablet (exclusive of any non-functional coating). Such colorants are available from a variety of sources including, e.g., Colorcon, Noveon, and Spectra. In one embodiment, no colorants are used in the tablet.

In order to facilitate production of the chewable tablet, excipients such as lubricants and glidants may be utilized. A lubricant may be utilized in an amount of about 0.1% w/w to about 5% w/w, about 0.2% w/w to about 4.5% w/w, or about 1.5% w/w to about 3% w/w of the total weight of the tablet. Examples of lubricants may include, e.g., magnesium stearate, sodium stearyl fumarate, stearic acid, zinc stearate, calcium stearate, magnesium trisilicate, polyethylene glycol, and blends thereof. In one embodiment, A glidant may be used in an amount of about 0.01% w/w to about 0.5% w/w, or about 0.1% w/w to about 0.3% w/w, based on the total weight of the tablet. Examples of suitable glidants include, e.g., silicon dioxide and tribasic calcium phosphate. In one embodiment, the glidant is silicon dioxide which is used in an amount of about 0.001% w/w to about 0.3% w/w or about 0.2% w/w.

Optionally, other excipients may be selected from conventional pharmaceutically acceptable carriers or excipients and well established techniques. Without being limited thereto, such conventional carriers or excipients include diluents, binders and adhesives (i.e., cellulose derivatives and acrylic derivatives), lubricants (i.e., magnesium or calcium stearate, or vegetable oils, polyethylene glycols, talc, sodium lauryl sulfate, polyoxy ethylene monostearate), thickeners, solubilizers, humectants, disintegrants, colorants, flavorings, stabilizing agents, sweeteners, and miscellaneous materials such as buffers and adsorbents in order to prepare a particular pharmaceutical composition. The stabilizing agents may include preservatives and anti-oxidants, amongst other components which will be readily apparent to one of ordinary skill in the art.

The following Tables provides exemplary formulations of amphetamine extended release compositions according to the invention, based on the total weight of the tablet.

Component Tablets % w/w % w/w Coated amphetamine - cation 20%-30% 25%-28% exchange resin complex - matrix (coated amphetamine polistirex - matrix) Uncoated amphetamine polistirex 1.5%-3.5% 2%-3% Uncomplexed amphetamine 0.5%-2%     1%-1.7%

Examples of suitable excipient amounts include those in the following table:

Component Tablets % w/w % w/w Filler(s)  45%-60%, 50%-55% e.g., Mannitol 40%-60% 36% to 42% Xanthan Gum 0.1%-1%   0.25%-0.75% MCC + guar gum  5%-25% 10%-20% Disintegrant(s)  7%-15%    10-15% Sweetener(s) 0%-3% 1%-2% Flavoring Agent 0.1%-3%   0.1%-1%   Lubricant(s) 0.2%-4.5% 1.5%-3%   0.1%-1.5% 0.5%-1%   Glidant 0.01%-1%   0.1%-0.3% Colorant   0%-0.5% 0.02%-0.08%

Suitably, a chewable tablet of the invention is prepared as a single uniform solid dispersion. A typical manufacturing process for making a chewable tablet generally involves blending of the desired ingredients to form a uniform distribution of the coated amphetamine-cation exchange resin complex, the uncoated amphetamine-cation exchange complex, the uncomplexed amphetamine, and the excipients. If desired, a blend of the amphetamine components may be formed prior to blending into the excipient. The blend is then compressed into a single layer using standard methods and tablet presses such as well-known to those skilled in the art (e.g., Kilian, Fette, Kirsch, Elizabeth, Sejong, Kikisui, SMI, Colton, Stok, and Manesty, amongst others.)

In one embodiment, a chewable tablet is produced in a round shape, caplet or capsule shape, optionally with a single bisect (a single scoring at the mid-line which facilitates splitting the tablet into halves). However, other shapes may be readily selected, including, e.g., a standard round shape, a flat faced shape, oval, bullet, square, triangle, diamond, pentagon, octagon, amongst others. Optionally, one or more of these tablet shapes may be provided with a quadrisect, i.e., two perpendicular scores which facilitate splitting the tablet into quarters.

Optionally, the chewable tablet may have one or more sealant or top coating which does not function to modify or extend the release of the amphetamine but which provides moisture barrier, of a color coating or other visual appeal. For example, such a coating may provide a “shine” to the tablet, enhance palatability, serve as an identifying color for the tablet, or other purposes. Such coatings are available commercially, e.g., from Colorcon or other suppliers. Typically, such a coating is composed of hydroxypropylmethylcellulose (HPMC) or polyvinylalcohol and is present in an amount of about 1% w/w to about 20% w/w, or about 2% w/w to about 10% w/w of the total tablet weight.

Suitably, the amphetamine extended release tablets can be scored without affecting the extended release profile. Thus, the oral dose is readily titrated, i.e., split in half, in order to readily and accurately deliver half the dose of the finished tablet. In one embodiment, a titratable, amphetamine chewable tablet of Example 2, and compositions bioequivalent thereto, are encompassed by the invention.

The finished compositions may be stored in glass or high density polyethylene (HDPE) bottles with or without a heat induced sealed (HIS) bottle. The bottle may also contain a dessicant. Alternatively, the tablets may be packaged into blister packs using standard methods well-known to those skilled in the art.

An amphetamine extended release composition as described herein may be orally administered to a patient having a disorder treatable by amphetamine. These include disorders for which regulatory approval has been granted in the US or other jurisdiction in which the drug is being administered and which requires regulatory approval. For example, amphetamine is currently approved for treatment of Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy. Amphetamine has also been described in patent applications and in the literature as being useful for treatment of other conditions or disorders including, but are not limited to, behavioral disorders, including Attention Deficit Disorder, treatment-resistant cases of lethargy, depression, obesity, weight loss, nasal congestion, neural insult, obesity, and rarely other psychiatric disorders such as obsessive-compulsive disorder, specific dyslexias, brain dysfunction, and cognitive decline. Berman et al, cited above.

Thus, a method of treating one or more of the above disorders for a period of at least eight hours, at least twelve hours, at least thirteen hours, or longer, by administering an amphetamine extended release composition is described herein. For example, a liquid suspension of the invention such as that of Example 1, or a bioequivalent thereto, may be administered. In another example, a chewable tablet or a bioequivalent thereof, may be administered. A composition of the invention is formulated to deliver amphetamine is, most desirably, in dosages ranging from about 1 mg up to about 20 mg per day, preferably from about 2.5 mg to about 20 mg per day, or in about 2.5 mg, 5 mg, 10 mg, 15 mg, or 20 mg doses [based on equivalence to amphetamine free base] although variations will necessarily occur depending upon the weight and condition of the subject being treated and the particular route of administration chosen. Variations may nevertheless occur depending upon the weight and condition of the persons being treated and their individual responses to said medicament.

As described herein, the amphetamine extended release compositions of the invention are dosed orally once per day in the morning, e.g, before 11 am. Optionally, smaller doses may be delivered in the morning and at intervals during the day. Other variations may be selected depending upon the patient.

An in vitro dissolution test determines whether chewable tablets, or the AMP-ion exchange complex solids of the liquid suspension, disintegrate within a prescribed time when placed in a dissolution media under prescribed experimental conditions. Disintegration is defined as the state in which no residue of the tablet, except fragments of undissolved coating, remains on the screen of the test apparatus or, if any other residue remains, it consists of a soft mass having no palpably firm, unmoistened core.

Examples of methods for in vitro testing of the compositions of the invention have been described, e.g., by the World Health Organization (WHO) International Pharmacopoeia, (http://www.who.int/medicines/publications/pharmacopoeia/). An example of a suitable disintegration apparatus is described as follows. The apparatus consists of a circular basket-rack assembly, a suitable vessel for the immersion fluid (such as a 1-litre beaker), a thermostatic arrangement for maintaining the fluid at the required temperature (normally 37±2° C.), and a device for raising and lowering the basket-rack in the immersion fluid at a constant frequency of 28-32 cycles/min through a distance of 50-60 mm. The basket-rack assembly consists of six open-ended cylindrical glass tubes and a rack for holding them in a vertical position. The tubes are 75-80 mm long, and have an inside diameter of about 21.5 mm and a wall about 2 mm thick. The tubes are held vertically by two superimposed plates, circular in shape and made of transparent plastic material, each about 90 mm in diameter and 6 mm thick, perforated by six holes of a diameter that allows the tubes to be inserted. The holes are equidistant from the center of the plate and equally spaced one from another. A piece of woven gauze, made of stainless steel wire about 0.635 mm in diameter, with a mesh aperture of 2.0 mm is attached to the underside of the lower plate. The upper plastic plate is covered with a stainless steel plate, about 1 mm thick, of a diameter similar to that of the plastic plates. The steel plate is perforated by six holes about 22 mm in diameter, positioned to coincide with those of the upper plastic plate. It is placed over the tubes and consolidates the whole structure. The plates are held rigidly 75-80 mm apart by vertical stainless steel rods at the periphery. A metal rod is fixed to the center of the upper plate. This enables the assembly to be attached to a suitable mechanical device so that it may be lowered and raised. The volume of the fluid in the immersion vessel should be such that, at the highest point of the upward stroke, the wire mesh that forms the bottom of the basket remains at least 25 mm below the surface of the fluid. At the lowest point of the downward stroke, it should descend to not less than 25 mm from the bottom of the vessel. The time required for the upward stroke should be equal to the time required for the downward stroke, and the change in stroke direction should be a smooth transition rather than an abrupt reversal of motion. Where a disc is prescribed in the monograph, the following configuration and dimensions apply: a cylindrical disc 20.7±0.15 mm in diameter and 9.5±0.15 mm thick, made of transparent plastic with a relative density of 1.18 to 1.20. Each disc is pierced by five holes 2 mm in diameter, one in the center and the other four spaced equally on a circle of radius 6 mm from the center of the disc. On the lateral surface of the disc, four equally spaced grooves are cut so that on the upper surface of the disc they are 9.5 mm wide and 2.55 mm deep and, at the lower surface, 1.6 mm square. Different designs of basket-rack assembly may be used, provided that the specifications for the glass tubes and the stainless steel wire gauze are maintained. In vino dissolution of the amphetamine compositions described herein may be assessed through a variety of methods including, e.g., Food and Drug Administration (FDA)-accepted dissolution tests, including the Basket Method (I) approved for use with an amphetamine chewable tablet, http://www.accessdata.fda.gov/scripts/cder/dissolution/dsp_SearchResults_Dissolutions.cfm, have been described. The current FDA-approved dissolution test for a prior art amphetamine tablet comprising Amphetamine Aspartate/Amphetamine Sulfate/Dextroamphetamine Saccharate/Dextroamphetamine Sulfate utilizes water and a paddle speed of 100 rpm, at 500 mL, with testing at 10, 20, 30 and 45 minutes; another prior art tablet containing dextroamphetamine sulfate uses the same test and volume, with testing at 10, 20, 30, 45 and 60 minutes. Two extended release capsules involve testing with Basket Method (II), 50 rpm, in a media of dilute HCl (pH 1.1 for first 2 hrs, then add 200 mL of 200 mM Phosphate Buffer and adjust to pH 6.0 for the remainder) and volume of 750 mL for 0-2 hours and after 2 hours 950 mL; with testing at 1, 2, 3, 4, and 4 or 6 hours (amphetamine ER). Other amphetamine products have different dissolution tests and different media. However, since the barrier coated amphetamine-cation exchange complex described herein is not readily soluble in water, the dissolution medium for the previously described tests are is not suitable for testing dissolution of the present tablets at those time frames. Accordingly, a dissolution medium of phosphate buffer described below may be used to assess in vino dissolution of the amphetamine compositions described herein rather than water.

In one embodiment, the compositions provided herein are characterized by an in vitro dissolution pattern for the amphetamine in the composition of one or more of: (a), (b), (c), (d) and/or (e), when said composition has the equivalent of 18.8 mg (about 20 mg) total amphetamines based on the weight of the total amphetamines in free base form:

-   -   (a) about 61±2 at about 0.5 hour, about 70±2 at about 1 hour,         about 79±2 at 2 hour, about 83±2 at 3 hours, about 86±1 at about         4 hours, about 89±1 at about 6 hours, about 90±1 at about 8         hours, and about 91±1 at about 12 hours as determined in about         900 mL of an in vitro dissolution media of about 0.1 N HCl USP         in Apparatus II at about 50 rpm;     -   (b) about 46±2 at about 0.5 hours, about 58±1 at about 1 hour,         about 68±1 at about 2 hours, about 74±1 at about 3 hours, about         77±1 at about 4 hours, about 81±1 at about 6 hours, about 82±1         at about 8 hours, and about 84±2 at about 12 hours, as         determined in about 900 mL of an in vitro dissolution media of         about pH 4.5 Acetate buffer in Apparatus II at about 50 rpm;     -   (c) about 63±2 at about 0.5 hours, about 75±1 at about 1 hour,         about 87±0 at about 2 hours, about 93±1 at about 3 hours, about         98±1 at about 6 hours, and about 101±1 at about 8 hours, as         determined in about 900 mL of about pH 6.8 USP media, in         Apparatus II at about 50 rpm;     -   (d) about 62±3 at about 0.5 hours, about 73±5 at about 1 hour,         about 82±6 at about 2 hours, about 92±2 at about 3 hours, about         95±2 at about 4 hours, as determined in about 750 mL at about pH         1.2 (2 hours) followed by phosphate buffer (about 200 mL), about         pH 6, in Apparatus II at about 50 rpm, and/or     -   (e) about 68±4 at about 0.5 hours, about 77±5 at about 1 hour,         about 87±3 at about 2 hours, about 92±2 at about 3 hours, about         94±2 at about 4 hours, about 96±2 at about 6 hours, about 98±2         at about 8 hours, and about 99±2 at about 12 hours, in about 900         mL of an in vitro dissolution media comprising about 0.9% NaCl         USP, in Apparatus II at about 50 rpm. These in vitro values were         generated using the composition of Example 5.

In one embodiment, an orally administrable extended release amphetamine composition provides, following a single dose of the composition in pediatric patients aged 6 to 12 years, the composition provides a pharmacokinetic profile for d-amphetamine and l-amphetamine of: geometric mean plasma AUC_(0-∞) of 910 h*ng/mL to 1115 h*ng/mL for d-amphetamine and 245 h*ng/mL to 400 h*ng/mL for l-amphetamine and a geometric mean plasma C_(max) of 45 ng/mL to 60 ng/mL for d-amphetamine and 14 ng/mL to 18 ng/mL for l-amphetamine; an arithmetic mean plasma AUC0-∞ of 845 h*ng/mL to 1330 h*ng/mL for d-amphetamine and 300 h*ng/mL to 480 h*ng/mL for 1-amphetamine and an arithmetic mean plasma C_(max) of 40 ng/mL to 70 ng/mL for d-amphetamine and 13 ng/mL to 22 ng/mL for l-amphetamine. In a further embodiment, the geometric mean plasma AUC_(0-∞) for d-amphetamine is 950 h*ng/mL to 1050 h*ng/mL for d-amphetamine and 300 h*ng/mL to 375 h*ng/mL for l-amphetamine and a geometric mean plasma C_(max) of 50 ng/mL to 55 ng/mL for d-amphetamine and 15 ng/mL to 17 ng/mL for l-amphetamine; and the arithmetic mean plasma concentration for d-amphetamine is 950 h*ng/mL to 1170 h*ng/mL for d-amphetamine and 340 h*ng/mL to 420 h*ng/mL for l-amphetamine and a mean plasma C_(max) of 48 ng/mL to 62 ng/mL for d-amphetamine and 15 ng/mL to 19 ng/mL for l-amphetamine. In still a further embodiment, wherein the geometric mean plasma AUC_(0-∞) for d-amphetamine is about 1013 h*ng/mL for d-amphetamine and for l-amphetamine is about 363 h*ng/mL and the geometric mean plasma C_(max) for d-amphetamine is about 53 ng/mL and for l-amphetamine is about 16 ng/mL the mean plasma AUC0-∞ for d-amphetamine is about 1060 h*ng/mL for d-amphetamine and for l-amphetamine is about 380 h*ng/mL and the mean plasma C_(max) for d-amphetamine is about 55 ng/mL and for 1-amphetamine is about 17 ng/mL.

In a further embodiment, the mean T_(max) is 3.5 hours to 4.2 hours for d-amphetamine and 4 hours to 5 hours for l-amphetamine; or the geometric mean T_(max) is about 3.8 for d-amphetamine and about 4.5 for l-amphetamine and the arithmetic mean is about 4 for d-amphetamine and about 4.8 for l-amphetamine.

In one embodiment, the extended release amphetamine composition contains, based on the total (free base) amphetamine in the composition, at least about 45% to about 75% w/w of the amphetamine is provided by modified release component, at least about 5% to about 20% w/w of the amphetamine is provided by immediate release component comprising unbound amphetamine, and at least 10% to about 30% w/w of the amphetamine is provided by immediate release component comprising amphetamine-ion exchange resin complex.

In one embodiment, the composition is an extended release suspension, wherein based on the weight of the total amphetamines as calculated on the basis of the free amphetamine bases, the modified release component. In one embodiment, each of the three components provides a ratio of d-amphetamine to l-amphetamine of about 3:about 1. In a further embodiment, the modified release component comprises at least 50% of the total amphetamines and the immediate release component comprising the amphetamine-ion exchange resin complex provides at least 35% of the total amphetamines.

In one embodiment, the composition contains only two counterions contributed by the free (unbound) amphetamine salt. In one embodiment, the suspension contains no more than 0.3% w/v of any single selected counterion. In another embodiment, the suspension contains no more than about 0.05% w/v of any selected counterion. In one example, the two different counterions are selected from aspartate and sulfate. In one embodiment, aspartate counterions are present in a concentration of 0.3% or less. In one example, the asparatate counterions are present in a concentration of about 0.010% w/v to up to 0.05% w/v. In another embodiment, sulfate counterions are present in a concentration of less than 0.001% w/v. In one example, the sulfate counterions are present in a concentration of about 0.05% w/v to up to 0.001% w/v, or 0.01 to 0.05% w/v. These amounts may be calculated empirically based on the amount of amphetamine salt added into the suspension.

In one embodiment, the extended release suspension has a therapeutic effect for attention deficit hyperactivity disorder with an onset at least as early as 1 hour and continuing through at least about 13 hours, in patients following administration of a dose equivalent to about 20 mg total amphetamines per 8 mL, based on the weight of the free base form of the amphetamines. In certain embodiments, the therapeutic effect last for up to about 18 hours following post-dose administration to a subject. In one embodiment, a suspension has a concentration of about 20 mg total amphetamines (based on the weight of the free base form of the amphetamines)/8 mL. However, other concentrations, e.g., of about 2.5 mg, 5 mg, 10 mg, 15 mg, or 20 mg per 1 mL to 8 mL, e.g., about 1 mL, about 2 mL, about 4 mL, about 6 mL may be readily selected.

In yet another aspect, the extended release amphetamine composition having the pharmacokinetic profile recited above is a chewable tablet. In one embodiment, the tablet is characterized by also being capable of functioning as an orally dissolving tablet.

In one embodiment, of the total amphetamines in the chewable tablet (based on free base of amphetamines), the modified release component contains about 35% to about 75%, or about 70% of the amphetamines, the immediate release component comprising the amphetamine-cation exchange resin complex provides about 5% to about 35%, or about 10% of the total amphetamines in the tablet, and the total unbound amphetamine is in the range of about 5% to about 25%, or about 20%, of the amphetamines. These tablets may be formulated as described previously in doses of 10, 15 and 20 mg equivalent to amphetamine (based on free base weight).

The following examples provide illustrative methods for making compositions of the invention.

EXAMPLES

The following examples are illustrative only and are not intended to be a limitation on the present invention.

Example 1—Amphetamine Extended Release (ER) Oral Suspension, Equivalent to 2.5 mg Amphetamine Base Per mL Coated (d, Dl) Amphetamine-Cation Exchange Resin Complex-Matrix

Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate (Amberlite 12000 g IRP69 ®) Cation Exchange Resin (dl) Amphetamine Sulfate 1440 g (d) - Amphetamine Sulfate 1560 g Purified Water 70 L (d, dl) Amphetamine - Cation Exchange Resin - Matrix Uncoated (d, dl) Amphetamine - Cation 10000 g Exchange Resin Complex Povidone (Kollidon ® 30D) 500 g Purified water 3500 g Coated (d, dl) Amphetamine - Cation Exchange resin Complex - matrix Polistirex - Matrix (d, dl) Amphetamine - Cation Exchange 3500 g Resin Complex - Matrix Polyvinyl Acetate Dispersion** (Kollicoat 3500 g SR30D) Triacetin 52.5 g Purified Water 1960 g Removed during processing **30% w/w aqueous dispersion

A. Uncoated (d, Dl) Amphetamine-Cation Exchange Resin Complex

The Drug-Resin Complex was prepared by first adding 70 L of Purified Water in to the process vessel and (dl) Amphetamine Sulfate and (d)-Amphetamine Sulfate were dissolved by continuous mixing. Sodium Polystyrene Sulfonate was dispersed with continuous mixing and the mixing was continued for 60 minutes. Water was removed by filtration process followed by rinsing twice using purified water (40 L). Wet resin complex was then dried until moisture content was between 3-7%. Dried drug-resin complex was passed through a 40 mesh screen using the CO-MIL. This was the Uncoated (d, dl) amphetamine-cation exchanger resin complex.

B. (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix

In a separate container Povidone was dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl) Amphetamine-cation exchange resin complex prepared as described in Part (A) was treated with Povidone solution with continuous mixing to form a uniform mass. Wet mass was dried until the moisture content was between 15-25%. Semi-dried material was then milled using CO-MIL brand mill fitted with 40 mesh screen. Milled material was further dried until moisture content was between 3-7%. Dried material was passed through a CO-MIL fitted with 40 mesh screen This was the (d, dl) amphetamine-cation exchange resin complex-matrix.

C. Coated (d, Dl) Amphetamine-Cation Exchange Resin Complex-Matrix

The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix was prepared as follows. The coating solution was prepared by mixing Triacetin, Purified Water and Polyvinyl Acetate dispersion in a separate container. The coating process was performed in a fluid bed processor equipped with Wurster column by applying coating solution on to (d, dl) Amphetamine-cation exchange resin complex-matrix as prepared in Part B, that resulted in 30% weight gain. The Coated (d, dl) Amphetamine-Cation Exchange Resin complex-matrix was placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl) Amphetamine-Cation exchange resin complex-Matrix was again passed through Sieve No. 40 mesh screen. This was the Coated (d, dl) Amphetamine-Cation Exchange Resin-Matrix.

Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propyl paraben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.25 11 (dl) Amphetamine Aspartate monohydrate 0.36 (uncomplexed) 12 (d) - Amphetamine Sulfate (uncomplexed) 0.51 13 Coated (d, dl) Amphetamine - Cation 11.43 Exchange Resin Complex - Matrix 14 Uncoated (d, dl) Amphetamine - Cation 4.79 Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

D. Preparation of Amphetamine Extended Release Oral Suspension

Glycerin (Item 1) was taken and heated to (65-75°) C. Methylparaben (Item 2) and propylparaben (Item 3) were added and mixed until completely dissolved (Paraben Solution). Cool the Paraben Solution to room temperature. Xanthan Gum (Item 4) was slowly added to the Paraben Solution and dispersed well (Gum dispersion). To main container purified water (Item 5) was taken and sucralose (Item 6) was added and mixed until dissolved. Starch Instant Clearjel (Item 7) was slowly added and mixed with the High Shear Mixer. Slowly add the Gum Dispersion to the main container while mixing with High Shear Mixer (mixing was continued for 10 minutes). and then mix on the Arrow mixer for additional 50 minutes. In a separate container purified water (Item 8) was added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. (dl-)Amphetamine Aspartate Monohydrate (Item 1), (d)-Amphetamine Sulfate (Item 12), Coated (d, d,l-) Amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d,dl)-Amphetamine-cation exchange resin complex (Item 14) were added and mixed at ambient condition for 1 hour. The mixture containing the coated and uncoated complexes was added to the main container and mixed for 60 minutes. Bubblegum flavor (Item 15) was added and mixed well for 30 minutes. Qs to final weight with purified water (Item 16) and mix for 30 minutes.

Example 2—Amphetamine Extended Release (ER) Chewable Tablets Equivalent to 10 mg, 15 mg & 20 mg Amphetamine

Item 10 mg No. Ingredient % w/w strength 15 mg 20 mg 1 Mannitol 39.05 91.32 136.98 188.28 2 Xanthan gum 0.5 1.2 1.8 2.4 3 Kollidon ® CL 12 28.8 43.2 57.6 Crospovidone 4 Avicel CE15 15 36 54 72 (Microcrystalline Cellulose (MCC) + guar gum 5 Sucralose 1.5 3.6 5.4 7.2 6 Citric Acid 1.0 2.4 3.6 4.8 7 Bubble gum flavor 0.5 1.2 1.8 2.4 8 Silicon dioxide 0.2 0.48 0.72 0.96 9 Magnesium 0.5 1.2 1.8 2.4 stearate 10 Uncoated (d, dl) - 2.698 6.48 9.72 12.95 amphetamine - cation exchange resin complex 11 Coated (d, dl) - 26.61 63.86 95.80 127.74 amphetamine - cation exchange resin complex - matrix 12 Dextro- 0.594 1.426 2.14 2.85 amphetamine sulfate (uncomplexed) 13 Amphetamine 0.85 2.04 3.06 4.085 aspartate monohydrate (uncomplexed) TOTAL 100 240 mg 360 mg 480 mg

The following weight percentages are based on the weight percentage of the total amount of the active drug in the dose using the weight of the free base equivalent, i.e., weight on the active drug calculate or measured without the weight of the coating, matrix polymer, polistirex, counterion, or hydrate form of the compound. The amount of coated (d, dl-) amphetamine-cation exchange resin complex-matrix is equivalent to about 70 wt % of the dose. The amount of uncoated (d, dl-) amphetamine-cation exchange resin complex is equivalent to about 10 wt % of the dose. The amount of dextroamphetamine sulfate is equivalent to 10.4 wt % of the dose (about 10⁰/), and the amount of amphetamine aspartate monohydrate is equivalent to 9.6% (about 10%).

The extended release chewable tablets containing amphetamines (10 mg, 15 mg & 20 mg strengths), are prepared as follows. Weigh the mannitol and microcrystalline cellulose and guar gum (Avicel CE15), and screen through a 20 mesh screen. Add the screened material into ‘V’-Blender. The xanthan gum, Kollidon® CL, sucralose, citric acid, bubble gum flavor, silicon dioxide, Uncoated Amphetamine-cation exchange resin complex, Coated Amphetamine-cation exchange resin complex-matrix, Dextroamphetamine Sulfate and Amphetamine Aspartate Monohydrate should each be weighed and passed through a #40 mesh screen. The screened material is added into a ‘V’-Blender (step 1). 3. Mix the powder blend for 15 minutes. Weigh Magnesium Stearate and pass through #40 mesh screen. Add the screened material into ‘V’-Blender as described in step 1. Mix this powder blend for 10 minutes. Unload the material from the Blender and compress into tablets by adjusting the appropriate tablet weight and hardness.

Example 3—Evaluation of Phase III Efficacy Study of Amphetamine Extended Release (ER) Liquid Suspension

The amphetamine ER liquid suspension prepared as described in Example 1, containing the equivalent of 2.5 mg/mL amphetamine base and a ratio of approximately 3:1 of d-amphetamine to l-amphetamine, was tested. The test involved children with attention deficit hyperactivity disorder (ADHD) aged 6-12 years old.

This formulation was assessed to study the attention and behavior of the subjects in a laboratory classroom using the Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) rating scale. Subjects with ADHD entered a 2-week randomized, double-blind, crossover treatment of the individually optimized dose of the amphetamine ER suspension (2.5 mg/daily to a maximum of 20 mg/daily) or placebo, administered once a day in the morning. At the end of each week, schoolteachers and raters evaluated the attention and behavior of the subjects in a laboratory classroom using the Swanson, Kotrin, Agler, M-Flynn, and Pelham (SKAMP) rating scale. Results of the study are summarized in FIG. 1 . SKAMP scores are statistically significantly lower (improved) during treatment with the amphetamine ER suspension of the invention as compared to placebo. Efficacy was observed at the earliest tested time point of 1 hour post-dose and efficacy was maintained throughout the entire 13-hour period.

Objective PK measurement occurred over 28 hours post-dose as a primary end point. Pediatric subjects are normally dosed in a manner to provide pharmacologic treatment primarily for the academic time period of the day as well as the after-school period. Two (2) age groups of pediatric subjects were included in this study: six (6) subjects between the ages of 6 to 9 and six subjects between the ages of 10 to 12. A total of 12 subjects, were enrolled in the study. This allows the comparison of PK parameters in younger and older pediatric patients treated with a single mid-range dose of amphetamine. A “mid-range” amphetamine dose refers to a comparison of 10 mg amphetamine base to equivalents of other amphetamine products currently FDA approved for the treatment of ADHD in pediatric patients. The study was performed under fasting conditions.

For PK analyses of amphetamine, 9 blood samples were collected in total from each subject. Samples were collected at pre-dose Day 1 (Time 0) and at the following times: Day 1: 1, 3, 4, 6, 8, 10, 12, and 28 hours post dose (Day 2). Time after dosing began when amphetamine was administered to the subject. With the exception of the 0 (pre-dose) and 28 hour sample, samples were collected within±5 minutes of the scheduled post-dose time. The pre-dose sample was collected up to 2 hours before dosing. The 28 hour sample was collected 26-30 hours post-dose.

The mean (±SD) plasma AUC_(inf) in pediatric patients between the ages of 6 to 12 years was 1061 (±309) h*ng/mL for d-amphetamine and 381 (±112) h*ng/mL for plasma l-amphetamine.

The mean (±SD) plasma C_(max) in pediatric patients between the ages of 6 to 12 years was 54.9 (±15.2) ng/mL and 17.1 (±5.2) ng/mL for d- and l-amphetamine respectively.

The maximum d- and l-amphetamine concentrations were reached around 3.43 hours (range of 2.92 to 5.93) and 4.05 hours (range of 2.92 to 7.93) post-dose, respectively.

The apparent elimination half-life estimated in the studied pediatric patients was 10.6 (±2.0) hours for d-amphetamine and 12.5 (±3.2) hours for 1-amphetamine.

The plasma concentration curves for d-amphetamine and l-amphetamine are provided in FIGS. 2 and 3 , respectively.

Example 4: Amphetamine ER Oral Suspension, Equivalent to 2.5 mg Amphetamine Base Per mL

A. Coated (d, dl) Amphetamine - Cation Exchange Resin Complex Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate (Amberlite 12000 g IRP69 ®) Cation Exchange Resin (dl) Amphetamine Sulfate 1440 g (d) - Amphetamine Sulfate 1560 g Purified Water* 70 L (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - Cation 10000 g Exchange Resin Complex Povidone 500 g Purified water* 3500 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation Exchange Resin 3500 g Complex - Matrix Polyvinyl Acetate Dispersion** (Kollicoat ® 3500 g SR30D) Triacetin 52.5 g Purified Water* 1960 g *Removed during processing **30% w/w aqueous dispersion

The amphetamine-cation exchange resin complex is prepared by first adding 70 L of Purified Water in to the process vessel, in which (dl-) Amphetamine Sulfate and (d-)amphetamine Sulfate are dissolved by continuous mixing. The cation exchange resin (Sodium Polystyrene Sulfonate) is dispersed in the process vessel with continuous mixing and the mixing is continued for 60 minutes. Water is removed by a filtration process followed by rinsing twice using purified water (40 L). The wet (d, dl)-amphetamine cation exchange resin complex is then dried until moisture content is between 3-7%. Dried drug-cation exchange resin complex is passed through a 40 mesh screen using the CO-MIL device. This is the uncoated (d, dl-) Amphetamine-cation exchange resin complex (the complex is alternatively termed Amphetamine Polistirex).

In a separate container Povidone is dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl-) amphetamine-cation exchange resin complex is treated with Povidone solution with continuous mixing to form a uniform mass. The wet mass is then milled using CO-MIL brand mill fitted with a 40 mesh screen. The milled material is dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL brand mill fitted with 40 mesh screen. This is the (d, dl-) amphetamine-cation exchange resin complex-matrix.

The coated (d, dl-) amphetamine-cation exchange resin complex-matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and the polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution on to (d, dl-) amphetamine-cation exchange resin complex-matrix that results in 30% weight gain. The coated (d, dl) amphetamine-cation exchange resin complex-matrix is placed in the hot air oven at 60° C. for 5 hours. The coated (d, dl) amphetamine-cation exchange resin complex-matrix is again passed through Sieve No. 40 mesh screen. This is the coated (d, dl) amphetamine-cation exchange resin complex-matrix.

B. Amphetamine Extended Release Oral Suspension: Item No. Ingredient g/batch 1 Purified Water 800 2 Sucralose 2 3 Starch Instant Clearjel 25.34 4 Polysorbate 80 1.1 5 Anhydrous Citric acid 2.25 6 (dl) Amphetamine Aspartate monohydrate 0.36 7 (d) - amphetamine Sulfate 0.51 8 Coated (d, dl) Amphetamine - Cation 11.43 Exchange Resin Complex - Matrix 9 Uncoated (d, dl) Amphetamine - Cation 4.79 Exchange Resin Complex 10 Bubblegum Flavor 2 11 Glycerin 100 12 Methylparaben 1.8 13 Propylparaben 0.2 14 Xanthan Gum 2.85 15 Purified Water QS to 1000 mL

Glycerin (Item 11) is taken and heated to 65-75° C. Methylparaben (Item 12) and Propylparaben (Item 13) are added and mixed until completely dissolved (Paraben Solution). The Paraben Solution is cooled to room temperature. Xanthan Gum (Item 14) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). Purified Water (Item 1) and Polysorbate 80 (Item 4) are added to the main container and mixed until dissolved. Sucralose (Item 2) and Anhydrous Citric Acid (Item 5) are then added and mixed until dissolved. Starch Instant Clearjel (Item 3) is slowly added and mixed with the High Shear Mixer. The Gum Dispersion is then slowly added to the main container while mixing with High Shear Mixer (mixing is continued for 10 minutes), followed by mixing on the Arrow mixer for an additional 50 minutes. (dl)-Amphetamine Aspartate Monohydrate (Item 6), (d)-amphetamine Sulfate (Item 7), Coated (d, dl)-Amphetamine-cation exchange resin complex-matrix (Item 8), Uncoated (d,dl) Amphetamine-Cation Exchange Resin Complex (Item 9) are added and mixed at ambient condition for 1 hour. Bubblegum Flavor (Item 10) is added and mixed well for 30 minutes. Purified Water (Item 15) is added q.s. and mixed for 30 minutes.

Example 5: Amphetamine Extended Release Oral Suspension

Coated (d, dl) Amphetamine Polistirex: Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Sodium Polystyrene Sulfonate (Amberlite 12000 g IRP ® 69) Cation Exchange Resin (dl) Amphetamine Sulfate 1440 g (d) - Amphetamine Sulfate 1560 g Purified Water* 70 L (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - Cation 11000 g Exchange Resin Povidone 550 g Purified water* 3450 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation Exchange 3400 g Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3740 g (Kollicoat ® SR30D) Triacetin 51 g Purified Water* 2094 *Removed during processing **30% w/w aqueous dispersion

The Drug-Resin Complex was prepared by first adding 70 L of Purified Water in to the process vessel and (dl) Amphetamine Sulfate and (d)-Amphetamine Sulfate were dissolved by continuous mixing. Sodium Polystyrene Sulfonate was dispersed with continuous mixing and the mixing was continued for 60 minutes. Water was removed by filtration process followed by rinsing twice using purified water (50 L). Wet resin complex was then dried until moisture content was between 3-7%. Dried drug-resin complex was passed through a 40 mesh screen using the CO-MIL. This was the Uncoated (d, dl) Amphetamine-Cation Exchange Resin Complex.

In a separate container Povidone was dissolved in 3200 g of Purified Water (Povidone solution). Uncoated (d, dl) Amphetamine-Cation Exchange Resin Complex was treated with Povidone solution with continuous mixing to form a uniform mass. Wet mass was dried until the moisture content was between 15-25%. Semi-dried material was then milled using CO-MIL brand mill fitted with 40 mesh screen. Milled material was further dried until moisture content was between 3-7%. Dried material was passed through a CO-MIL brand mill fitted with 40 mesh scren. This was the (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix.

The Coated (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrixwas prepared as follows. The coating solution was prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process was performed in a fluid bed processor equipped with Wurster column by applying coating solution on to (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrixthat resulted in 30% weightgain. The Coated (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix was placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix was again passed through Sieve No. 40 mesh screen. This was the Coated (d, dl) Amphetamine Cation Exchange Resin Complex-Matrix.

B. Amphetamine ER Oral Suspension: Item No. Ingredient kg/batch 1 Purified Water 258.44 2 Sucralose 0.738 3 Starch Instant Clearjel 9.131 4 Polysorbate 80 0.406 5 Anhydrous Citric acid 0.831 6 Coated (d, dl) Amphetamine - Cation 3.065 Exchange Resin Complex - Matrix 7 Uncoated (d, dl) 1.511 Amphetamine - Cation Exchange Resin Complex 8 Bubblegum Flavor 0.738 9 Glycerin 36.92 10 Methylparaben 0.665 11 Propylparaben 0.074 12 Xanthan Gum 1.015 13 Purified Water QS to 369.2 L

In a vessel, glycerin (Item 9) is added and heated to 65-75° C. Methylparaben (Item 10) and propylparaben (Item 11) were added and mixed until completely dissolved (Paraben Solution). Cool the Paraben Solution to room temperature. Xanthan gum (Item 12) was slowly added to the Paraben solution and dispersed well (Gum dispersion). Purified water (Item 1) and polysorbate 80 (Item 4) was added to the main container and mixed until dissolved. Sucralose (Item 2) and anhydrous citric acid (Item 5) were added and mixed until dissolved. Starch Instant Clearjel (Item 3) was slowly added and mixed with the high shear mixer. The Gum Dispersion is slowly added to the main container while mixing with High Shear Mixer (mixing was continued for 10 minutes), and then mix on the Arrow mixer for additional 50 minutes. The coated (d, dl) Amphetamine-cation exchange resin complex-matrix prepared in Part A (Item 6) and Uncoated (d,dl) Amphetamine-cation exchange resin complex prepared in Part A (Item 7) were added and mixed at ambient condition for 1 hour. Bubblegum Flavor (Item 10) was added and mixed well for 30 minutes. Purified water (Item 15) is added qs to final weight and mixed for 30 minutes.

Example 6: Amphetamine Extended Release Oral Suspension

A. Coated (d, dl) Amphetamine Polistirex: Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate 12000 g (Amberlite ® IRP69) Cation Exchange Resin (dl) Amphetamine Sulfate 1440 g (d) - Amphetamine Sulfate 1560 g Purified Water* 70 L (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - 10000 g Cation Exchange Resin Complex Povidone 500 g Purified water* 3500 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation 3500 g Exchange Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3500 g (Kollicoat ® SR30D) Triacetin 52.5 g Purified Water* 1960 g *Removed during processing **30% w/w aqueous dispersion

The Drug-Resin Complex is prepared by first adding 70 L of Purified Water in to a process vessel and dissolving (dl) Amphetamine Sulfate and (d)-Amphetamine Sulfate by continuous mixing. Sodium Polystyrene Sulfonate is dispersed with continuous mixing and the mixing is continued for 60 minutes. Water is removed by filtration process followed by rinsing twice using purified water (40 L). The wet (d,dl)-amphetamine-cation exchange resin complex is then dried until the moisture content is between 3-7%. The dried amphetamine-cation exchange resin complex is passed through a 40 mesh screen using the CO-MIL brand mill. This is the Uncoated (d, dl) Amphetamine-cation exchange resin complex.

In a separate container, Povidone is dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl) Amphetamine-cation exchange resin complex is treated with Povidone solution with continuous mixing to form a uniform mass. The wet mass is dried until the moisture content is between 15-25%. Semi-dried material is then milled using CO-MIL brand mill fitted with a 40 mesh screen. Milled material is further dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL brand mill fitted with a 40 mesh screen. This is the (d, dl) Amphetamine-cation exchange resin complex-matrix.

The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution onto (d, dl) amphetamine-cation exchange resin complex-matrix that results in 30% weight gain. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is again passed through a Sieve No. 40 mesh screen. This is the Coated (d, dl) Amphetamine-cation exchange resin complex-matrix.

B: Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propylparaben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.25 11 (dl) Amphetamine Aspartate 0.36 monohydrate 12 (d) - Amphetamine Sulfate 0.51 13 Coated (d, dl) Amphetamine - 11.43 Cation Exchange Resin Complex - Matrix 14 Uncoated (d, dl) 4.79 Amphetamine - Cation Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

Glycerin (Item 1) is heated to 65-75° C. Methylparaben (Item 2) and propylparaben (Item 3) are added and mixed until completely dissolved (Paraben Solution). The Paraben Solution is cooled to room temperature. Xanthan Gum (Item 4) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). Purified water (Item 5) and sucralose (Item 6) was added to the main container and mixed until dissolved. (dl) Amphetamine Aspartate Monohydrate (Item 11), (d)-Amphetamine Sulfate (Item 12) are then added and mixed until dissolved. Starch Instant Clearjel (Item 7) is slowly added and mixed with the high shear mixer. The Gum Dispersion is slowly added to the main container while mixing with a high shear mixer (mixing is continued for 10 minutes), followed by mixing on the Arrow mixer for an additional 50 minutes. In a separate container purified water (Item 8) is added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. Coated (d, dl) amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d,dl) amphetamine-cation exchange resin complex (Item 14) are added and mixed at ambient condition for 1 hour (Slurry). The resin slurry from step 10 is added to the main container and mixed for 60 minutes. Bubblegum Flavor(Item 15) is added and mixed well for 30 minutes. Purified water (Item 16) is added qs to achieve the final weight and mixed for 30 minutes.

Example 7—Amphetamine Extended Release (ER) Chewable Tablets Equivalent to 10 mg, 15 mg &20 mg Amphetamine

10 mg Item No. Ingredient % w/w strength 15 mg 20 mg 1 Lactose 39.35 94.44 141.66 188.88 2 Xanthan gum 1.8 4.32 15.552 8.64 3 Crospovidone 12 28.80 43.20 57.56 4 Microcrystalline 12 28.80 43.20 57.50 Cellulose MCC 5 Sucralose 1.5 3.6 5.4 7.2 6 Citric Acid 1.0 2.4 3.6 4.8 7 Bubble gum flavor 0.5 1.2 1.8 2.4 8 Silicon dioxide 0.2 0.48 0.72 0.96 9 Magnesium stearate 0.5 1.2 1.8 2.4 10 Uncoated (d, dl) - 2.7 6.48 9.72 12.95 amphetamine - cation exchange resin complex 11 Coated (d, dl) - 27 63.86 95.80 127.74 amphetamine - cation exchange resin complex - matrix 12 Dextroamphetamine .6 1.426 2.14 2.85 sulfate (uncomplexed) 13 Amphetamine aspartate 0.85 2.04 3.06 4.085 monohydrate (uncomplexed) TOTAL 100 240 mg 360 mg 480 mg

The extended release chewable tablets containing amphetamines (10 mg, 15 mg & 20 mg strengths), are prepared as follows using the coated (d, dl)-amphetamine-cation exchange resin complex-matrix and uncoated (dl, d)-amphetamine-cation exchange resin complex prepared as described in Example 1. Weigh the lactose and microcrystalline cellulose, and screen through a 20 mesh screen Add the screened material into ‘V’-Blender. The xanthan gum, crospovidone, sucralose, citric acid, flavor, silicon dioxide, Uncoated Amphetamine-cation exchange resin complex. Coated Amphetamine-cation exchange resin complex-matrix, Dextroamphetamine Sulfate and Amphetamine Aspartate Monohydrate should each be weighed and passed through a #40 mesh screen. The screened material is added into a ‘V’-Blender. The powder blend is mixed for 15 minutes. Weigh Magnesium Stearate and pass through 1140 mesh screen. Add the screened material into ‘V’-Blender as described above. Mix this powder blend for 10 minutes. Unload the material from the Blender and compress into tablets by adjusting the appropriate tablet weight and hardness.

Example 8—Amphetamine Extended Release (ER) Chewable Tablets Equivalent to 10 mg, 15 mg & 20 mg Amphetamine

Item 10 mg No. Ingredient % w/w strength 15 mg 20 mg 1 Lactose 39.35 94.44 141.66 188.88 2 Xanthan gum 1.8 4.32 15.552 8.64 3 Crospovidone 12 28.80 43.20 57.56 4 Microcrystalline 12 28.80 43.20 57.50 Cellulose MCC 5 Sucralose 1.5 3.6 5.4 7.2 6 Citric Acid 1.0 2.4 3.6 4.8 7 Bubble gum flavor 0.5 1.2 1.8 2.4 8 Silicon dioxide 0.2 0.48 0.72 0.96 9 Magnesium stearate 0.5 1.2 1.8 2.4 10 Uncoated d - 1.35 3.24 4.86 6.475 amphetamine - cation exchange resin complex 11 Uncoated (d,l) - 1.35 3.24 4.86 6.475 amphetamine - cation exchange resin complex 12 Coated d - 13.5 31.93 47.9 63.87 amphetamine - cation exchange resin complex - matrix 13 Coated (d,l) - 13.5 31.93 47.9 63.87 amphetamine - cation exchange resin complex - matrix 14 Dextroamphetamine 0.6 1.426 2.14 2.85 sulfate (uncomplexed) 15 Amphetamine aspartate 0.85 2.04 3.06 4.085 monohydrate (uncomplexed) TOTAL 100 240 mg 360 mg 480 mg

Separate uncoated d-amphetamine-cation exchange resin and (d,l)-amphetamine-cation exchange resins are prepared essentially as described in Example 1, with the exception that in place of blending the d-amphetamine and (d,l)-amphetamine salts together with the sodium polystyrene sulfonate (Amberlite® IRP69) cation exchange resin, the complexes are formed separately, i.e., d-amphetamine sulfate and the cation exchange resin are mixed and reacted in one reaction. More particularly, the uncoated complex is prepared by first adding 70 L of purified water in to the process vessel and dissolving (dl)-Amphetamine Sulfate by continuous mixing. Sodium Polystyrene Sulfonate cation exchange resin is dispersed with continuous mixing and mixing is continued for 60 minutes. Water is removed by filtration process followed by rinsing twice using purified water (40 L). Wet resin complex is then dried until moisture content was between 3-7%. Dried drug-resin complex is passed through a 40 mesh screen using the CO-MIL. This is the Uncoated (dl) Amphetamine-Cation Exchange Resin Complex. A similar process is performed by substitutingd-amphetamine Sulfate in order to afford the uncoated d-amphetamme-cation exchange resin complex. One portion of each the separate uncoated (d,l)-amphetamine-cation exchange resin complex and uncoated d-amphetamine-cation exchange resin are set aside for the final formulation and another portion of each of the separate complexes are treated with the matrix forming polymer to afford the (d,l)-amphetamine-cation exchange resin complex-matrix and the d-amphetamine-cation exchange resin complex-matrix. These drug-complex-matrix particles are subsequently processed as described in Example 1 with the coating material to afford the coated (d,l)-amphetamine-cation exchange resin complex-matrix and the coated d-amphetamine-cation exchange resin complex-matrix.

The extended release chewable tablets containing amphetamines (10 mg, 15 mg & 20 mg strengths), are prepared as follows. Weigh the lactose and microcrystalline cellulose, and screen through a 20 mesh screen. Add the screened material into ‘V’-Blender. The xanthan gum, crospovidone, sucralose, citric acid, flavor, silicon dioxide, Uncoated (d,l)-Amphetamine-cation exchange resin complex and uncoated d-Amphetamine-cation exchange resin complex, Coated (d,l)-Amphetamine-cation exchange resin complex-matrix and Coated d-Amphetanne-cation exchange resin complex-matrix. Dextroamphetamine Sulfate and Amphetamine Aspartate Monohydrate should each be weighed and passed through a #40 mesh screen. The screened material is added into a ‘V’-Blender and the powder blend is mixed for 15 minutes. Weigh magnesium stearate and pass through #40 mesh screen. Add the screened material into ‘V’-Blender as described above. Mix this powder blend for 10 minutes. Unload the material from the Blender and compress into tablets by adjusting the appropriate tablet weight and hardness.

Example 9: Amphetamine Extended Release Oral Suspension

A. Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix: Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate 12000 g (Amberlite ® IRP69) Cation Exchange Resin (dl) Amphetamine Aspartate Monohydrate 2240 g (d) - phetamine Sulfate 1560 g Purified Water* 70 L Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - 10000 g Cation Exchange Resin Complex Povidone 500 g Purified water* 3500 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation 3500 g Exchange Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3500 g (Kollicoat ® SR30D) Triacetin 52.5 g Purified Water* 1960 g *Removed during processing **30% w/w aqueous dispersion

The Drug-Resin Complex is prepared by first adding 70 L of Purified Water into a process vessel and dissolving (dl)-Amphetamine Aspartate Monohydrate and (d)-Amphetamine Sulfate by continuous mixing. Sodium Polystyrene Sulfonate is dispersed with continuous mixing and the mixing is continued for 60 minutes. Water is removed by filtration process followed by rinsing twice using purified water (40 L). The wet (d, dl)-amphetamine-cation exchange resin complex is then dried until the moisture content is between 3-7%. The dried amphetamine-cation exchange resin complex is passed through a 40 mesh screen using the CO-MIL brand mill. This is the Uncoated (d, dl)-Amphetamine-cation exchange resin complex.

In a separate container, Povidone is dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl)-Amphetamine-cation exchange resin complex is treated with Povidone solution with continuous mixing to form a uniform mass. The wet mass is dried until the moisture content is between 15-25%. Semi-dried material is then milled using CO-MIL brand mill fitted with a 40 mesh screen. Milled material is further dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL brand mill fitted with a 40 mesh screen. This is the (d, dl)-Amphetamine-cation exchange resin complex-matrix.

The Coated (d, dl)-Amphetamine-cation exchange resin complex-matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution onto (d, dl)-amphetamine-cation exchange resin complex-matrix that results in 30% weight gain. The Coated (d, dl)-Amphetamine-cation exchange resin complex-matrix is placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl)-Amphetamine-cation exchange resin complex-matrix is again passed through a Sieve No. 40 mesh screen. This is the Coated (d, dl)-Amphetamine-cation exchange resin complex-matrix.

B: Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propylparaben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.25 11 (dl) - Amphetamine Sulfate 0.33 12 (d) - Amphetamine Sulfate 0.51 13 Coated (d, dl) - Amphetamine - 11.43 Cation Exchange Resin Complex - Matrix 14 Uncoated (d, dl) - 4.79 Amphetamine - Cation Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

Glycerin (Item 1) is heated to 65-75° C. Methylparaben (Item 2) and propylparaben (Item 3) are added and mixed until completely dissolved (Paraben Solution). The Paraben Solution is cooled to room temperature. Xanthan Gum (Item 4) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). Purified water (Item 5) and sucralose (Item 6) are added to the main container and mixed until dissolved. (dl)-Amphetamine Aspartate Monohydrate (Item 11), (d)-Amphetamine Sulfate (Item 12) are then added and mixed until dissolved. Starch Instant Clearjel (Item 7) is slowly added and mixed with the high shear mixer. The Gum dispersion is slowly added to the main container while mixing with a high shear mixer (mixing is continued for 10 minutes), followed by mixing on the Arrow mixer for an additional 50 minutes. In a separate container purified water (Item 8) is added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. Coated (d, dl)-Amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d,dl)-Amphetamine-cation exchange resin complex (Item 14) are added and mixed at ambient condition for 1 hour. This resin mixture is added to the main container and mixed for 60 minutes. Bubblegum Flavor (Item 15) is added and mixed well for 30 minutes. Purified water (Item 16) is added qs to achieve the final weight and mixed for 30 minutes.

Example 10: Amphetamine Extended Release Oral Suspension

A. Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix: Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate 18000 g (Amberlite ® IRP69) Cation Exchange Resin (dl) - Amphetamine Sulfate 1440 g d - Amphetamine Sulfate 1560 g Purified Water* 70 L Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - 10000 g Cation Exchange Resin Complex Povidone 500 g Purified water* 3500 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation 2500 g Exchange Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3492 g (Kollicoat ® SR30D) Triacetin 53 g Purified Water* 1956 *Removed during processing **30% w/w aqueous dispersion

The Drug-Resin Complex is prepared by first adding 70 L of Purified Water in to the process vessel and (dl)-Amphetamine Sulfate and d-Amphetamine Sulfate were dissolved by continuous mixing. Sodium Polystyrene Sulfonate is dispersed with continuous mixing and the mixing is continued for 60 minutes. Water is removed by filtration process followed by rinsing twice using purified water (50 L). Wet resin complex is then dried until moisture content is between 3-7%. Dried drug-resin complex is passed through a 40 mesh screen using the CO-MIL. This is the Uncoated (d, dl) Amphetamine-Cation Exchange Resin Complex.

In a separate container Povidone is dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl)-Amphetamine-Cation Exchange Resin Complex is treated with Povidone solution with continuous mixing to form a uniform mass. Wet mass is dried until the moisture content is between 15-25%. Seml-dried material is then milled using CO-MIL brand mill fitted with 40 mesh screen. Milled material is further dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL brand mill fitted with 40 mesh screen. This is the (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix.

The Coated (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution onto (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix that results in 40% weight gain. The Coated (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix is placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl) Amphetamine-Cation Exchange Resin Complex-Matrix is again passed through Sieve No. 40 mesh screen. This is the Coated (d, dl) Amphetamine Cation Exchange Resin Complex-Matrix.

B: Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propylparaben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.25 11 (dl) Amphetamine Sulfate 0.33 12 (d) - Amphetamine Sulfate 0.51 13 Coated (d, dl) Amphetamine - 11.45 Cation Exchange Resin Complex - Matrix 14 Uncoated (d, dl) 4.79 Amphetamine - Cation Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

Glycerin (Item 1) is heated to 65-75° C. Methylparaben (Item 2) and propylparaben (Item 3) are added and mixed until completely dissolved (Paraben Solution). The Paraben Solution is cooled to room temperature. Xanthan Gum (Item 4) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). Purified water (Item 5) and sucralose (Item 6) is added to the main container and mixed until dissolved. (dl) Amphetamine Aspartate Monohydrate (Item 11), (d)-Amphetamine Sulfate (Item 12) are then added and mixed until dissolved. Starch Instant Clearjel (Item 7) is slowly added and mixed with the high shear mixer. The Gum dispersion is slowly added to the main container while mixing with a high shear mixer (mixing is continued for 10 minutes), followed by mixing on the Arrow mixer for an additional 50 minutes. In a separate container purified water (Item 8) is added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. Coated (d, dl) amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d,dl) amphetamine-cation exchange resin complex (Item 14) are added and mixed at ambient condition for 1 hour. The resin mixture is added to the main container and mixed for 60 minutes. Bubblegum Flavor (Item 15) is added and mixed well for 30 minutes. Purified water (Item 16) is added qs to achieve the final weight and mixed for 30 minutes.

Example 11: Amphetamine Extended Release Oral Suspension

Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate 12000 g (Amberlite IRP69 ®) Cation Exchange Resin (dl) Amphetamine Sulfate 1440 g (d) - Amphetamine Sulfate 1560 g Purified Water 70 L Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - 10000 g Cation Exchange Resin Complex Povidone (Kollidon ® 30D) 500 g Purified water 3500 g Coated (d, dl) Amphetamine - Cation Exchange resin Complex - Matrix (d, dl) Amphetamine - Cation 3500 g Exchange Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3500 g (Kollicoat SR30D1 Triacetin 52.5 g *Purified Water 1960 g *Removed during processing **30% w/w aqueous dispersion

A. Uncoated (d, Dl) Amphetamine-Cation Exchange Resin Complex

The Drug-Resin Complex is prepared by first adding 70 L of Purified Water into the process vessel; (dl) Amphetamine Sulfate and (d)-Amphetamine Sulfate are dissolved by continuous mixing. Sodium Polystyrene Sulfonate is dispersed with continuous mixing and the mixing is continued for 60 minutes. Water is removed by filtration followed by rinsing twice using purified water (40 L). Wet resin complex is then dried until moisture content is between 3-7%. Dried drug-resin complex is passed through a 40 mesh screen using the CO-MIL brand mill. This is the Uncoated (d, dl) amphetamine-cation exchanger resin complex.

B. Uncoated (d, Dl) Amphetamine-Cation Exchange Resin Complex-Matrix

In a separate container Povidone is dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl) Amphetamine-cation exchange resin complex prepared as described in Part (A) is treated with Povidone solution with continuous mixing to form a uniform mass. Wet mass is dried until the moisture content is between 15-25%. Semi-dried material is then milled using CO-MIL brand mill fitted with 40 mesh screen. Milled material is further dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL fitted with a 40 mesh screen. This is the (d, dl) amphetamine-cation exchange resin complex-matrix.

C. Coated (d, Dl) Amphetamine-Cation Exchange Resin Complex-Matrix

The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution onto (d, dl) Amphetamine-cation exchange resin complex-matrix as prepared in Part B, to 30% weight gain. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl)) Amphetamine-cation exchange resin complex-matrix is again passed through Sieve No. 40 mesh screen. This is the coated (d, dl) amphetamine-cation exchange resin-matrix.

D: Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propylparaben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.35 11 (dl) Amphetamine Aspartate 0.26 monohydrate (uncomplexed) 12 (d) - Amphetamine Sulfate 0.18 (uncomplexed) 13 Coated (d, dl) Amphetamine - 13.71 Cation Exchange Resin Complex - Matrix 14 Uncoated (d, dl) Amphetamine - 4.79 Cation Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

Glycerin (Item 1) is taken and heated to (65-75°) C. Methylparaben (Item 2) and propylparaben (Item 3) are added and mixed until completely dissolved (Paraben Solution). Cool the Paraben Solution to room temperature. Xanthan Gum (Item 4) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). To main container purified water (Item 5) is taken and sucralose (Item 6) was added and mixed until dissolved. Starch Instant Clearjel (Item 7) is slowly added and mixed with the High Shear Mixer. Slowly add the Gum dispersion to the main container while mixing with High Shear Mixer (mixing is continued for 10 minutes) and then mix on the Arrow mixer for additional 60 minutes. In a separate container purified water (Item 8) is added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. (dl) Amphetamine Aspartate Monohydrate (Item 1), (d)-Amphetamine Sulfate (Item 12), Coated (d, dl) Amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d, dl) Amphetamine-cation exchange resin complex (Item 14) are added and mixed at ambient condition for 1 hour. The resin suspension mixture containing the coated and uncoated complexes is added to the main container and mixed for 60 minutes. Bubblegum flavor (Item 15) is added and mixed well for 30 minutes. Qs to final weight with purified water (Item 16) and mix for 30 minutes.

Example 12: Amphetamine Extended Release Oral Suspension

A. Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix: Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate 10000 g (Amberlite ® IRP69) Cation Exchange Resin (dl) Amphetamine Sulfate 1200 g (d) - Amphetamine Sulfate 1300 g Purified Water* 70 L (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - 10000 g Cation Exchange Resin Complex Povidone 500 g Purified water* 3500 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation 3500 g Exchange Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3500 g (Kollicoat ® SR30D) Triacetin 52.5 g Purified Water* 1960 g *Removed during processing **30% w/w aqueous dispersion

The Drug-Resin Complex is prepared by first adding 70 L of Purified Water into a process vessel and dissolving (dl) Amphetamine Sulfate and (d)-Amphetamine Sulfate by continuous mixing. Sodium Polystyrene Sulfonate is dispersed with continuous mixing and the mixing is continued for 60 minutes. Water is removed by filtration process followed by rinsing twice using purified water (40 L). The wet (d, dl) amphetamine-cation exchange resin complex is then dried until the moisture content is between 3-7%. The dried amphetamine-cation exchange resin complex is passed through a 40 mesh screen using the CO-MIL brand mill. This is the Uncoated (d, dl) Amphetamine-cation exchange resin complex.

In a separate container, Povidone is dissolved in 3500 g of Purified Water (Povidone solution). Uncoated (d, dl) Amphetamine-cation exchange resin complex is treated with Povidone solution with continuous mixing to form a uniform mass. The wet mass is dried until the moisture content is between 15-25%. Semi-dried material is then milled using CO-MIL brand mill fitted with a 40 mesh screen. Milled material is further dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL brand mill fitted with a 40 mesh screen. This is the (d, dl) Amphetamine-cation exchange resin complex-matrix.

The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution onto (d, dl) amphetamine-cation exchange resin complex-matrix that results in 30% weight gain. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is again passed through a Sieve No. 40 mesh screen. This is the Coated (d, dl) Amphetamine-cation exchange resin complex-matrix.

Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propylparaben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.25 11 (dl) Amphetamine 0.64 Aspartate monohydrate 12 (d) - Amphetamine Sulfate 0.45 13 Coated (d, dl) Amphetamine - 10.28 Cation Exchange Resin Complex - Matrix 14 Uncoated (d, dl) 4.79 Amphetamine - Cation Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

Glycerin (Item 1) is heated to 65-75° C. Methylparaben (Item 2) and propylparaben (Item 3) are added and mixed until completely dissolved (Paraben Solution). The Paraben Solution is cooled to room temperature. Xanthan Gum (Item 4) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). Purified water (Item 5) and sucralose (Item 6) are added to the main container and mixed until dissolved. (dl) Amphetamine Aspartate Monohydrate (Item 11), (d)-Amphetamine Sulfate (Item 12) are then added and mixed until dissolved. Starch Instant Clearjel (Item 7) is slowly added and mixed with the high shear mixer. The Gum dispersion is slowly added to the main container while mixing with a high shear mixer (mixing is continued for 10 minutes), followed by mixing on the Arrow mixer for an additional 60 minutes. In a separate container purified water (Item 8) is added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. Coated (d, dl) amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d,dl) amphetamine-cation exchange resin complex (Item 14) are added and mixed at ambient condition for 1 hour. This mixture is added to the main container and mixed for 60 minutes. Bubblegum Flavor (Item 15) is added and mixed well for 30 minutes. Purified water (Item 16) is added qs to achieve the final weight and mixed for 30 minutes.

Example 13—Amphetamine Extended Release Oral Suspension

A. Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix: Ingredients Quantity Uncoated (d, dl) Amphetamine - Cation Exchange Resin Complex Sodium Polystyrene Sulfonate 10000 g (Amberlite ® IRP69) Cation Exchange Resin (dl) Amphetamine Sulfate 1200 g (d) - Amphetamine Sulfate 1300 g Purified Water* 70 L (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix Uncoated (d, dl) Amphetamine - 10000 g Cation Exchange Resin Complex Povidone 700 g Purified water* 4900 g Coated (d, dl) Amphetamine - Cation Exchange Resin Complex - Matrix (d, dl) Amphetamine - Cation 3500 g Exchange Resin Complex - Matrix Polyvinyl Acetate Dispersion** 3500 g (Kollicoat ® SR30D) Triacetin 52.5 g Purified Water* 1960 g *Removed during processing **30% w/w aqueous dispersion

The Drug-Resin Complex is prepared by first adding 70 L of Purified Water into a process vessel and dissolving (dl) Amphetamine Sulfate and (di)-Amphetamine Sulfate by continuous mixing. Sodium Polystyrene Sulfonate is dispersed with continuous mixing and the mixing is continued for 60 minutes. Water is removed by filtration process followed by rinsing twice using purified water (40 L). The wet (d, dl) amphetamine-cation exchange resin complex is then dried until the moisture content is between 3-7%. The dried amphetamine-cation exchange resin complex is passed through a 40 mesh screen using the CO-MIL brand mill. This is the Uncoated (d, dl) Amphetamine-cation exchange resin complex.

In a separate container, Povidone is dissolved in 4900 g of Purified Water (Povidone solution). Uncoated (d, dl) Amphetamine-cation exchange resin complex is treated with Povidone solution with continuous mixing to form a uniform mass. The wet mass is dried until the moisture content is between 15-25%. Semi-dried material is then milled using CO-MIL brand mill fitted with a 40 mesh screen. Milled material is further dried until moisture content is between 3-7%. Dried material is passed through a CO-MIL brand mill fitted with a 40 mesh screen. This is the (d, dl) Amphetamine-cation exchange resin complex-matrix.

The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is prepared as follows. The coating solution is prepared by mixing triacetin, purified water and polyvinyl acetate dispersion in a separate container. The coating process is performed in a fluid bed processor equipped with Wurster column by applying coating solution onto (d, dl) amphetamine-cation exchange resin complex-matrix that results in 30% weight gain. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is placed in the hot air oven at 60° C. for 5 hours. The Coated (d, dl) Amphetamine-cation exchange resin complex-matrix is again passed through a Sieve No. 40 mesh screen. This is the Coated (d, dl) Amphetamine-cation exchange resin complex-matrix.

B. Amphetamine ER Oral Suspension: Item No. Ingredient g/batch 1 Glycerin 100 2 Methylparaben 1.8 3 Propylparaben 0.2 4 Xanthan Gum 2.85 5 Purified Water 600 6 Sucralose 2 7 Starch Instant Clearjel 25.34 8 Purified Water 200 9 Polysorbate 80 1.1 10 Anhydrous Citric acid 2.25 11 (dl) Amphetamine Aspartate 0.80 monohydrate 12 (d) - Amphetamine Sulfate 0.51 13 Coated (d, dl) Amphetamine - 11.43 Cation Exchange Resin Complex - Matrix 14 Uncoated (d, dl) 3.19 Amphetamine - Cation Exchange Resin Complex 15 Bubblegum Flavor 2 16 Purified Water QS to 1000 mL

Glycerin (Item 1) is heated to 65-75° C. Methylparaben (Item 2) and propylparaben (Item 3) are added and mixed until completely dissolved (Paraben Solution). The Paraben Solution is cooled to room temperature. Xanthan Gum (Item 4) is slowly added to the Paraben Solution and dispersed well (Gum dispersion). Purified water (Item 5) and sucralose (Item 6) was added to the main container and mixed until dissolved. (dl) Amphetamine Aspartate Monohydrate (Item 11), (d)-Amphetamine Sulfate (Item 12) are then added and mixed until dissolved. Starch Instant Clearjel (Item 7) is slowly added and mixed with the high shear mixer. The Gum dispersion is slowly added to the main container while mixing with a high shear mixer (mixing is continued for 10 minutes), followed by mixing on the Arrow mixer for an additional 60 minutes. In a separate container purified water (Item 8) is added. Polysorbate 80 (Item 9) and anhydrous citric acid (Item 10) are added and mixed until dissolved. Coated (d, dl) amphetamine-cation exchange resin complex-matrix (Item 13), Uncoated (d,dl) amphetamine-cation exchange resin complex (Item 14) are added and mixed at ambient condition for 1 hour. This resin mixture is added to the main container and mixed for 60 minutes. Bubblegum Flavor (Item 15) is added and mixed well for 30 minutes. Purified water (Item 16) is added qs to achieve the final weight and mixed for 30 minutes.

All patents, patent publications, and other publications listed in this specification, are incorporated herein by reference. While the invention has been described with reference to a particularly preferred embodiment, it will be appreciated that modifications can be made without departing from the spirit of the invention. Such modifications are intended to fall within the scope of the appended claims. 

What is claimed is:
 1. An orally administrable extended release amphetamine liquid suspension comprising: (A) at least one modified release component comprising an amphetamine-cation exchange resin complex-optional matrix, wherein the amphetamine-cation exchange resin complex comprises (i) two or more amphetamines both bound to the same cation exchange resin or each bound to a different cation exchange resins, wherein when the optional matrix is present, the amphetamine-cation exchange resin complex-matrix further comprises a hydrophilic polymer or copolymer or a hydrophobic polymer and (ii) a water-insoluble, water-permeable, pH-independent barrier coating which provides a sustained or extended release to the two or more amphetamines, wherein the two or more amphetamines are at least a d-amphetamine and an l-amphetamine, wherein the d-amphetamine and the l-amphetamine are provided by d-amphetamine and at least one of (d,l)-amphetamine and l-amphetamine; (B) a first immediate release amphetamine component which comprises d-amphetamine or a pharmaceutically acceptable salt thereof, and l-amphetamine or a pharmaceutically acceptable salt thereof, or mixtures thereof, wherein the d- and l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine and l-amphetamine; and (C) a second immediate release amphetamine component which comprises an amphetamine-cation exchange resin complex in an optional matrix, wherein the amphetamine-cation exchange resin complex-optional matrix comprises at least a d-amphetamine and an l-amphetamine both bound to the same cation exchange resin or each bound to different cation exchange resins, wherein the d-amphetamine and the l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine or l-amphetamine; wherein none of the amphetamine components in the suspension has a delay release coating which delays the release of the amphetamines, wherein the suspension provides at least one immediate release profile for d-amphetamine and for l-amphetamine and a therapeutic profile for at least 13 hours for d-amphetamine and for l-amphetamine; and wherein the suspension comprises a ratio of about 3 parts by weight d-amphetamine to about 1 part by weight l-amphetamine.
 2. The orally administrable extended release amphetamine suspension according to claim 1, wherein following a single dose of the suspension in a pediatric patient 6 to 12 years of age, the suspension provides a pharmacokinetic profile for d-amphetamine and l-amphetamine of: geometric mean plasma AUC_(0-∞) of about 910 h*ng/mL to about 1115 h*ng/mL for d-amphetamine and about 245 h*ng/mL to about 400 h*ng/mL for 1-amphetamine and a geometric mean plasma C_(max) of about 45 ng/mL to about 60 ng/mL for d-amphetamine and about 14 ng/mL to about 18 ng/mL for 1-amphetamine.
 3. The orally administrable extended release amphetamine suspension according to claim 2, wherein the geometric mean plasma AUC_(0-∞) for d-amphetamine is about 950 h*ng/mL to about 1050 h*ng/mL for d-amphetamine and about 300 h*ng/mL to about 375 h*ng/mL for l-amphetamine and a geometric mean plasma C_(max) of about 50 ng/mL to about 55 ng/mL for d-amphetamine and about 15 ng/mL to about 17 ng/mL for l-amphetamine.
 4. The orally administrable extended release amphetamine suspension according to claim 2, wherein the geometric mean plasma AUC_(0-∞) for d-amphetamine is about 1013 h*ng/mL for d-amphetamine and for l-amphetamine is about 363 h*ng/mL and the geometric mean plasma C_(max) for d-amphetamine is about 53 ng/mL and for l-amphetamine is about 16 ng/mL.
 5. The orally administrable extended release suspension according to claim 1, wherein the suspension contains two different amphetamine counterions.
 6. The orally administrable extended release suspension according to claim 5, wherein the two different counterions are aspartate and sulfate.
 7. The orally administrable extended release suspension according to claim 6, wherein the aspartate counterions are present in a concentration of about 0.01% w/v to up to 0.05% w/v.
 8. The orally administrable extended release suspension according to claim 6, wherein the sulfate counterions are present in a concentration of about 0.01% w/v to up to 0.05% w/v.
 9. The orally administrable extended release aqueous liquid suspension according to claim 1, which comprises 20 mg total amphetamines per 8 mL, wherein the weight of total amphetamines is determined on the basis of amphetamine base in the amphetamine components.
 10. A method for treating a patient having attention deficit hyperactivity disorder, said method comprising delivering to the patient an orally administrable extended release suspension according to claim
 1. 11. The method according to claim 10, wherein the therapeutic effect lasts up to about 18 hours following post-dose administration to a patient.
 12. The method according to claim 10, wherein following a single dose of the suspension in a pediatric patient 6 to 12 years of age, the suspension provides a pharmacokinetic profile for d-amphetamine and l-amphetamine of: geometric mean plasma AUC0-∞ of about 910 h*ng/mL to about 1115 h*ng/mL for d-amphetamine and about 245 h*ng/mL to about 400 h*ng/mL for 1-amphetamine and a geometric mean plasma Cmax of about 45 ng/mL to about 60 ng/mL for d-amphetamine and about 14 ng/mL to about 18 ng/mL for 1-amphetamine.
 13. The method according to claim 10, wherein following a single dose of the suspension in a pediatric patient 6 to 12 years of age, the suspension provides a pharmacokinetic profile for d-amphetamine and l-amphetamine of: (a) geometric mean plasma AUC0-∞ for d-amphetamine is about 950 h*ng/mL to about 1050 h*ng/mL for d-amphetamine and about 300 h*ng/mL to about 375 h*ng/mL for 1-amphetamine and a geometric mean plasma Cmax of about 50 ng/mL to about 55 ng/mL for d-amphetamine and about 15 ng/mL to about 17 ng/mL for 1-amphetamine, and/or (b) geometric mean plasma AUC0-∞ for d-amphetamine is about 1013 h*ng/mL for d-amphetamine and for 1-amphetamine is about 363 h*ng/mL and the geometric mean plasma Cmax for d-amphetamine is about 53 ng/mL and for 1-amphetamine is about 16 ng/mL.
 14. An orally administrable extended release amphetamine liquid suspension comprising: (A) at least one modified release component comprising an amphetamine-cation exchange resin complex-optional matrix, wherein the amphetamine-cation exchange resin complex comprises (i) two or more amphetamines both bound to the same cation exchange resin, wherein when the optional matrix is present, the amphetamine-cation exchange resin complex-matrix further comprises a hydrophilic polymer or copolymer or a hydrophobic polymer and (ii) a water-insoluble, water-permeable, pH-independent, barrier coating which provides a sustained or extended release to the two or more amphetamines, wherein the two or more amphetamines of (i) are at least a d-amphetamine and an l-amphetamine, wherein the d-amphetamine and the l-amphetamine are provided by d-amphetamine and at least one of (d,l)-amphetamine and l-amphetamine; (B) a first immediate release amphetamine component which comprises d-amphetamine or a pharmaceutically acceptable salt thereof, and l-amphetamine or a pharmaceutically acceptable salt thereof, or mixtures thereof, wherein the d- and l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine and l-amphetamine; and (C) a second immediate release amphetamine component which comprises an amphetamine-cation exchange resin complex in an optional matrix, wherein the amphetamine-cation exchange resin complex-optional matrix comprises at least a d-amphetamine and an l-amphetamine both bound to the same cation exchange resin, wherein the d-amphetamine and the l-amphetamine are provided by d-amphetamine and at least one of (d, l)-amphetamine or l-amphetamine; wherein none of the amphetamine components in the suspension has a delay release coating which delays the release of the amphetamines, wherein based on the weight of the total amphetamines as calculated on the basis of the free base amphetamines, the modified release component (A) comprises 45% to 75% by weight of the total amphetamines in the suspension, the immediate release component (B) comprises 5% to 25% by weight of the total amphetamines in the suspension, and immediate release (C) comprises 30% to 40% by weight of the total amphetamines in the suspension; and wherein the suspension provides at least one immediate release profile for d-amphetamine and for l-amphetamine and a therapeutic profile for at least 13 hours for d-amphetamine and for l-amphetamine; wherein the suspension comprises a ratio of about 3 parts by weight d-A amphetamine to about 1 part by weight l-amphetamine.
 15. The orally administrable extended release suspension according to claim 14, wherein the modified release component (A) comprises at least 55% of the total amphetamines and the second immediate release component (C) comprises at least 35% of the total amphetamines.
 16. The orally administrable extended release suspension according to claim 14, wherein the water-insoluble, water-permeable, barrier coating of (A) comprises: (a) a cured, water-permeable, non-ionic, pH-independent barrier coating comprising polyvinylacetate, a stabilizer, and a plasticizer; (b) an ionic, pH-independent, acrylic based coating comprising a polymer or copolymer comprising ethyl acrylate and methyl methacrylate applied as an aqueous dispersion; or (c) a solvent-based ethylcellulose, optionally with a plasticizer.
 17. The orally administrable extended release aqueous liquid suspension according to claim 16, wherein the barrier coating is a cured, water-insoluble, water-permeable, non-ionic, pH-independent barrier coating comprising about 70 to about 90% w/w polyvinylacetate, a stabilizer, and about 2 to about 10% w/w of a plasticizer.
 18. A method for treating a patient having attention deficit hyperactivity disorder, said method comprising delivering to the patient an orally administrable extended release suspension according to claim
 14. 